Damaged Genesis Yields Data on Solar Wind
The goal of NASA's Genesis mission was to collect samples of the solar wind and return them to Earth for study. The Genesis spacecraft spent 27 months in space, gathering tiny particles from different types of solar wind. It then returned to Earth and ejected its sealed sample capsule for Earth re-entry and a gentle airborne recovery by helicopter. Unfortunately the planned parachute-capture of the capsule was not possible because the parachute failed to deploy. The sad result was the creation of a new small crater in the Utah desert. Observers of the crash were initially devastated, but the mission team soon realized that data could still be salvaged, though more slowly and with more effort.
The results, picked from millimeter-sized shards of the spacecraft's detectors, provide a snapshot of the early solar system, and will feed into models that outline how our planet’s atmosphere evolved.
The team originally hoped they could publish a series of papers within a year of the return. It has taken much longer, but as of late October a series of four papers had been published in Space Science Reviews and a fifth paper appeared the week of October 14 in Science. In addition, a preliminary paper was published last year.
The team remains hopeful that they will soon be able to complete the main goal of their original mission: solving the mystery of the unique isotopic signature of different objects in our galaxy.
The recent paper in Science contains a study of the ratio of different isotopes of neon and argon obtained from samples of three types of solar wind: fast, slow, and coronal mass ejections from the sun’s surface. The researchers conclude that these ratios are essentially the same in all three types of wind. This is good news: it indicates that the elements of main interest to the researchers have the same isotopic signature in the solar wind as in the sun itself.
That’s useful because the outer layer of the sun is thought to provide a picture of isotopic ratios in the very early solar system, before stars or planets were formed. Scientists had previously been concern that there would be a difference between the compositions of the solar wind and the sun itself.
The isotopic ratios of neon and argon are not in themselves very surprising — scientists already had a fairly good measure of these values from previous missions, including one low-tech scheme during the Apollo program in which a screen was laid out on the Moon to collect solar-wind samples. But they improve by a factor of 60 the precision with which the argon isotope ratio is known. This will be useful for researchers who model the early solar system to work out processes such as how Earth’s atmosphere formed.
As expected, the Genesis samples have a heavy contamination of Earth dirt and air. But surprisingly, the grit that is proving most problematic for the team at this point is a fine layer of lubricants and other craft-building materials that coated the samples. The coating was expected, but it is proving tricky to deal with.
Earth contamination can be separated from the samples mainly because the solar wind particles penetrated deep into the collector cells, a depth of approximately 40 nanometers.
The study of neon and argon was not affected as much by Earth contamination because dirt and air on Earth contain relatively little neon and argon.
The team remains hopeful that they will be able to get results on oxygen and nitrogen isotopes from the mission. To do this, they plan to examine a collecting dish that, although banged up and dirtied by the landing, seems to have succeeded in gathering up enough of these elements for measurement.
Scientists are interested in nitrogen because on the Moon, isotopes of this element vary greatly between the collected soil samples, even though all nitrogen is thought to come from the solar wind. Researchers want to know the reason for this variation.
Oxygen isotopes are even odder, as they seem to have unique ‘fingerprint’ values in different types of objects. For example if given a rock sample, scientists can measures oxygen isotopes and determine whether it is from Earth or space or the Moon. But put they are still trying to understand why. By knowing the value in the Sun, and hence the early Solar System, they expect to pin down the reason for this oddity.
Some are even confident that with more work and a few more years, they will also get oxygen and nitrogen.
To learn more about the Genesis mission, visit these websites:
http://www.nasa.gov/genesis
http://genesis.lanl.gov/
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MARS IS COMING, PART 4
As the December 24 opposition approaches, please enjoy this fourth installment on the Red Planet Mars.
The Atmosphere (Part 2)
Quick Atmospheric Temperature Overview:
- Surface: Cyclic temperatures range from approximately 189 K (-119 °F, -84 °C) to 240 K (-28 °F, -33 °C)
- Lower atmosphere: Altitude of a few kilometers up to 40 km (a few miles up to 25 miles). Temperature decreases at a rate of .5 K per km.
- Tropopause: 40 km to 100 km (25 miles to 60 miles).
- Above 100 km (above 60 miles): Average temperature of about 300 K (80 °F, 27 °C).
Atmospheric Constituents:
Below about 125 km (80 miles), the Martian atmosphere is composed of 95.5% carbon dioxide and small amounts of nitrogen, water vapor and argon, with trace amounts of other gases. To put some of these components in perspective, carbon dioxide is responsible for the Greenhouse Effect and is used for carbonation in beverages, nitrogen is a crucial element in DNA, and argon is used to make blue neon light blubs.
Atmospheric structure
Even though the Martian atmosphere is very thin by comparison to Earth’s, it is still very dynamic and very complex. The relation of temperature and pressure to the altitude--sometimes called the vertical structure of the atmosphere--is determined by two factors. One is a complicated balance of several mechanisms that spread energy through the atmosphere. The other is the way in which the sun's energy is introduced into the atmosphere and then lost by radiation to space.
In the lower atmosphere, the vertical structure is controlled by a combination of almost-pure carbon dioxide and the large amount of suspended dust. Carbon dioxide radiates energy efficiently at the colder (relative to Earth) Martian temperatures, so the atmosphere responds quickly to changes in the amount of solar radiation it receives. The suspended dust absorbs large quantities of heat directly from sunlight and distributes the energy throughout the lower atmosphere.
Like Earth, Martian surface temperatures depend on the latitude. But the temperatures fluctuate over a wider range from day to night. At the Viking 1 and Pathfinder landing sites, both of which are about 20° N latitude, the temperatures at roughly human height above the surface regularly varied from a low near 189 K (-119 °F, -84 °C) just before sunrise to a high of 240 K (-28 °F, -33 °C) in the early afternoon—an amazing range of about 51 K or 51 °C or 91 °F. This temperature swing is much greater than that of the desert regions on Earth. The variation is greatest very close to the ground where the thin, dry atmosphere allows the surface to radiate its heat quickly during the night. During dust storms this ability is restricted, and the temperature swing is reduced. At altitudes above a few kilometers, the daily variation is damped out, but other cyclic changes appear throughout the atmosphere because of the sun’s energy. The temperature and pressure cycles are sometimes called “tides” because they are regular, periodic, and synchronized with the position of the sun. These tides give the Martian atmosphere a very complex vertical structure.
Up to about 40 km (25 miles) the atmosphere gradually cools at a rate of .5 K per km.
Beginning at that level, called the tropopause, the temperature becomes a roughly constant 140 K (-210 °F, -130 °C). This was measured by the Viking and Pathfinder spacecraft as they descended through the atmosphere. Before these measurements were taken, scientists thought the tropopause began at about 15 km (9 miles), and the rate of temperature drop leading up to that altitude was thought to be near 5 K per km. The large amount of dust suspended in the atmosphere is thought to be responsible for the differences.
Above 100 km (60 miles), the structure of the atmosphere is determined by the tendency of the heavier molecules to settle below the lighter ones. This diffusive separation process overcomes the tendency of turbulence to mix all the constituents together. At these high altitudes, absorption of ultraviolet light from the sun dissociates and ionizes the gases and leads to complex sequences of chemical reactions. The top of the atmosphere has an average temperature of about 300 K (80 °F, 27 °C).
Meteorology and atmospheric dynamics
The global pattern of atmospheric circulation on Mars appears similar to that of Earth, but the root causes are very different. Among these differences are the atmosphere's ability to adjust rapidly to local conditions of solar heat input; the lack of oceans, which on Earth have a large resistance to temperature changes; the great range in altitude of the surface; the strong internal heating of the atmosphere because of suspended dust; and the seasonal deposition and release of a large part of the Martian atmosphere at the poles.
The only direct measurements of wind speeds were made by the Viking and Pathfinder landers. Near-surface winds at the landing sites were usually regular in behavior and generally light. Average speeds were typically less than 2 meters per second (4.5 miles per hour), although gusts up to 40 meters per second (90 miles per hour) were recorded. Other observations, including streaks of windblown dust and patterns in dune fields and in the many varieties of clouds, provide additional clues about surface winds.
Global circulation models, which incorporate all the factors understood to influence the behavior of the atmosphere, predict that the winds are strongly needed to create the Martian seasons because of the large horizontal temperature gradients associated with the edge of the polar caps in the fall and winter. Strong jet streams with eastward velocities above 100 meters per second (225 miles per hour) form at high latitudes in winter. Atmosphere circulation is less dramatic in spring and fall, when light winds predominate everywhere. On Mars, unlike on Earth, there is also a relatively strong north-south circulation that transports the atmosphere to and from the winter and summer poles. The general circulation pattern is occasionally unstable and exhibits large-scale wave motions and instabilities: a regular series of rotating high- and low-pressure systems was clearly seen in the pressure and wind records at the Viking lander sites.
Smaller-scale motions and circulations, driven both by the sun and by surface topography, are found everywhere. For example, at the Viking and Pathfinder landing sites, the winds change in direction and speed throughout the day in response to the position of the sun and the local slope of the land.
Turbulence is an important factor in raising and maintaining the large quantity of dust found in the atmosphere. Dust storms tend to begin at certain locations in the southern hemisphere during the southern spring and summer. Activity is at first local and strong (for reasons yet to be understood), and large amounts of dust are thrown high into the atmosphere. If the amount of dust reaches a critical quantity, the storm quickly intensifies, and dust is carried by high winds to all parts of the planet. In a few days the storm hides the entire surface, and visibility is reduced to less than 5 percent of normal. The strengthening process is short-lived and the atmosphere begins to clear almost immediately, becoming normal typically in a few weeks.
Next Time: "The Polar Caps"
Bibliography
Mars. (2007). In Encyclopædia Britannica. Retrieved October 26, 2007 , from Encyclopædia Britannica Online: http://www.britannica.com/eb/article-9110149
Mars (2007). In The Columbia Encyclopedia, Sixth Edition 2007. Copyright 2007 Columbia University Press. Retrieved October 26, 2007 from Encyclopedia.com
http://www.encyclopedia.com/doc/1E1-Mars-ast.html
Planets: Mars. In NASA Solar System Exploration, Last updated October 23, 2007. Retrieved October 26, 2007, from the NASA Solar System Exploration website, maintained by NASA's Jet Propulsion Laboratory:
http://solarsystem.jpl.nasa.gov/planets/profile.cfm?Object=Mars
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THE SKY THIS WEEK
Nov 24, 9:30 AM EST - Full Moon. Called the "Beaver Moon" or "Snow Moon," this was the time to set beaver traps before the swamps froze, in order to ensure a supply of winter furs. Others suggest the name refers to the fact that beavers were actively preparing for winter. This full moon is also sometimes called the "Frosty Moon."
Nov 24 – The planet Uranus is stationary. The body appears motionless in the sky due to the turning point between its direct and retrograde motion.
Nov 27 – The planet Mars is 1.7° south of the Moon
Nov 28 – The planet Venus is 4° north of the star Spica
Nov 30 - the star Regulus 0.3° north of the Moon, an occultation as seen from some locations. An occultation occurs when one object passes in front of a smaller one, temporarily obscuring all or part of the background object from view.
Dec 1, 7:44 A.M. EST - Last Quarter Moon
Dec 1 – The planet Saturn is 2° north of Moon
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SPACE EXPLORATION THIS WEEK
Nov 30 - Ulysses, begins its third north polar pass of the sun
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THIS WEEK IN HISTORY
Nov 26, 1965 - Asterix 1 Launch, France's 1st Satellite Launch
Nov 26, 1999 - Discovery of SAU 005 & 008, two Mars Meteorites
Nov 27, 1701 - Birthday of Anders Celsius, Swedish astronomer (1701-1744). Celsius developed a thermometer which had 100 points between the freezing point (100) and boiling point (0) of water. The scale was later reversed by Carolus Linnaeus so that the freezing point was 0 and the boiling point was 100. This temperature scale is named in his honor.
Nov 27, 1971 - Mars 2, Mars Orbit Insertion
Nov 28, 1700 - Birthday of Nathaniel Bliss, British astronomer, succeeded James Bradley to be the fourth Astronomer Royal, serving from 1762 until his death in 1764.
Nov 28, 1964 - Mariner 4 Launch, Mars Flyby Mission
Nov 29, 1961 - Mercury 5 Launch with Enos the Chimpanzee
Nov 29, 1967 - Wresat 1 Launch, Australia's 1st Satellite, 40th Anniversary
Nov 29, 2000 - Discovery of Y000593 Meteorite, a Mars Meteorite
Nov 30, 1954 - Sylacauga Meteorite Fall, Hit Woman
Dec ??, 2000 - Discovery of NWA 817 Meteorite, a Mars Meteorite
Dec 1, 1960 - Sputnik 6 Launch, Carried Two Dogs: Pchelka & Mushka
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MUSICAL DIVERSION
According to a 1580 entry in the Stationers’ Register, license was given to a Richard Jones to print “A new Northern Dittye of the Lady Green-Sleeves.” This was one of the first references to the song known today as “Greensleeves.” The other reference appeared the same year, by Edward White, entitled "A ballad, being the Ladie Greene Sleeves Answere to Donkyn his frende." The earliest surviving lyrics are in a collection called A Handful of Pleasant Delights (1584). The actual “Greensleeves” tune first appeared in 1652.
Many stories have developed around the song. According to legend, King Henry VIII of England (1491-1547) wrote the song for Anne Boleyn during their courtship, around 1530. However, this has never been proven and is probably not true. But it is also said that Henry’s daughter Queen Elizabeth I danced to the song. The song’s tune was used as the basis for a number of other lyrics, including a political ballad of the day. Even William Shakespeare mentioned “Greensleeves” twice (in Act Two and Act Five) in his play, “The Merry Wives of Windsor.”
The lyrics show the song to be a plea from a 16th century gentleman to his bored mistress. Here are some of the recorded lyrics for the song.
Greensleeves
Alas, my love you do me wrong
To cast me off discourteously
And I have loved you so long
Delighting in your company
Chorus:
Greensleeves was all my joy
Greensleeves was my delight
Greensleeves was my heart of gold
And who but my Lady Greensleeves.
I have been ready at your hand
to grant whatever you would crave;
I have both wagered life and land
Your love and good will for to have
(chorus)
I bought the kerchers to thy head
That were wrought fine and gallantly
I kept thee both at board and bed
Which cost my purse well favouredly.
(chorus)
Greensleeves, now farewell! adieu!
God I pray to prosper thee;
For I am still thy lover true
Come once again and love me.
(chorus)
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One of the tune’s early appearances in a hymn was entitled “The Old Yeare Now Away Is Fled.” Then about 1865, English poet and lay theologian William Chatterton Dix published a poem entitled "The Manger Throne." Dix was already known for other carols, including "As With Gladness Men of Old" (1859). Portions of Dix’s new poem were later adapted for the tune "Greensleeves," creating the carol that we know as "What Child Is This?" It is not known who combined the words with the tune, but it may have been John Stainer (1840-1901), since Stainer wrote a harmonization for the song. Stainer published the song in his 1871 collection entitled Christmas Carols New and Old. Below is the text from that publication.
What Child Is This
What Child is this who, laid to rest
On Mary’s lap is sleeping?
Whom angels greet with anthems sweet,
While shepherds watch are keeping?
Chorus:
This, this is Christ the King,
Whom shepherds guard and angels sing;
Haste, haste, to bring Him laud,
The Babe, the Son of Mary.
Why lies He in such mean estate,
Where ox and ass are feeding?
Good Christians, fear, for sinners here
The silent Word is pleading.
Chorus:
Nails, spear shall pierce Him through,
The cross be borne for me, for you.
Hail, hail the Word made flesh,
The Babe, the Son of Mary.
So bring Him incense, gold and myrrh,
Come peasant, king to own Him;
The King of kings salvation brings,
Let loving hearts enthrone Him.
Chorus:
Raise, raise a song on high,
The virgin sings her lullaby.
Joy, joy for Christ is born,
The Babe, the Son of Mary.
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To review some the history, the text, or to listen to the melody, check out this pages from the "Songs of England" section of "Contemplations from the Marianas Trench - Music and Deep Thoughts" - http://www.contemplator.com/england/grenslevs.html
To see and hear more on the hymn, “"What Child Is This?" visit this page of "The Cyber Hymnal" - http://www.cyberhymnal.org/htm/w/h/whatcist.htm
Monday, November 26, 2007
Sunday, November 18, 2007
WEEKLY UPDATE
Astronomer Questions Significance of COBE Images
Most astronomers say the Cosmic Background Explorer (COBE) satellite images show structures of the early universe. But 70-year-old radio astronomer and author Gerrit Verschuur of the University of Memphis, claims to have evidence that the images actually depict nearby hydrogen gas clouds in our own galaxy, calling into question one of the most important theories in the past 15 years. Verschuur's research will be published December 10 in the Astrophysical Journal.
NASA scientists announced in 1992 that their COBE satellite had imaged the ultimate baby pictures of the universe, revealing the seeds that grew into galaxies like our own Milky Way. And in 2003, higher-resolution images of the seeds were taken by another satellite, the Wilkinson Microwave Anisotropy Probe (WMAP).
According to Verschuur's research, the imaged seeds are located not on the edge of the universe, but nearby. Instead, they're just previously unmapped clouds of "neutral hydrogen" gas located inside the Milky Way. Verschuur sites at least 200 instances where the so-called cosmic seeds lie suspiciously close to known hydrogen clouds inside our galaxy.
Scientists who have reviewed his work suggest Verschuur’s correlations between the WMAP seeds and galactic hydrogen filaments are just coincidences. But as history has shown with previous debates over statistical interpretations, it is likely that Verschuur’s claim will not be settled anytime soon.
To learn more about the Cosmic Background Explorer (COBE) mission, visit the NASA website:
http://lambda.gsfc.nasa.gov/product/cobe/
Wilkinson Microwave Anisotropy Probe (WMAP) mission, visit the NASA website:
http://map.gsfc.nasa.gov/
Hubble Images Do Not Explain Comet 17P/Holmes Outburst
Astronomers are still uncertain what caused the brightening of normally-dim Comet 17P/Holmes, which erupted October 24 and is still shining brightly like a new star in the constellation Perseus.
In a November 15 announcement, three new comet images taken by the Hubble Space Telescope (HST) showed the core of Holmes as a field of particles extending some 15,000 miles across. The images also show that the particles appear to be coming from around the comet's hidden nucleus. This information, combined with another image taken by a ground-based telescope at the Calgary Science Centre (CSC) in Alberta, Canada, supplements the idea of some scientists that something must have broken off from around the nucleus and then disintegrated to become the dust cloud.
According to astronomers, the most likely explanation for the outburst is that a coating of relatively stable water ice, less than 10 miles thick around the comet's nucleus, was suddenly blown away by other, far more volatile chemical ices beneath the frozen water. As those ices heated and expanded violently, they blew the outer ice apart.
The new HST images show no large fragments in the cloud of particles that might suggest they were fragments of the nucleus itself or debris from a collision with a boulder-size asteroid orbiting between Mars and Jupiter - although some astronomers already have proposed that idea.
Seven years ago, HST imaged Comet Holmes, then nearly 150 million miles away. Astronomers inferred from the comet's brightness that its nucleus of rock and ice was barely more than 2 miles wide and that no dust obscured it. But the three new HST images have identified the 15,000-mile core of particles closest to the nucleus.
In addition, the new CSC image shows that at its brightest, the comet's particles extend for at least 2 million miles, with a thinner scattering of particles on its lower right side that may be the beginning of a comet tail.
When British amateur astronomer Edwin Holmes discovered the comet in November of 1892, he detected it because it had suddenly burst into a huge ball of light in his telescope. It then dimmed and, 73 days later, flared up briefly again.
At the time, U.S. astronomer Fred Whipple suggested that the flare-ups occurred because the comet had a double nucleus. Whipple proposed that one nucleus hit the other in a "grazing collision" that triggered the comet's first brilliant cloud of gas and dust, and then a full head-on crash 73 days later created the spectacular second outburst. In recalling Holmes' discovery, some will be watching in mid-January, hoping for a second display.
Still others suggest this year's flare-up might have resulted from a fragile nucleus spinning so fast that it just flew apart.
Astronomers at the Space Telescope Science Institute are studying the feasibility of a 2015 NASA mission to Comet Holmes or some other comet that has a history of flare-ups, and to orbit it long enough to learn the cause and maybe return a sample of the particles.
To learn more, visit Hubble Site, home of NASA's Hubble Space Telescope: http://hubblesite.org/
To learn more about the Calgary Science Centre in Alberta, Canada, visit their website: http://www.calgaryscience.ca/
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MARS IS COMING, PART 3
As the December 24 opposition approaches, please enjoy this third installment on the Red Planet Mars.
The Atmosphere (Part 1)
In 1947, Dutch-American astronomer Gerard P. Kuiper (1905-1973) determined from telescopic observations that the Martian atmosphere is composed mainly of carbon dioxide. The atmosphere is very thin, pushing at less than 1 percent of Earth's atmospheric pressure at the surface. The altitude varies greatly over the Martian surface, causing surface pressures to range over a factor of 15. Today's atmosphere has only small amounts of water. If it all was extracted and frozen, it would form a layer of ice crystals only 10 micrometers (0.0004 inch) thick, which could be gathered into a solid block of ice not much larger than one of Earth's medium-size icebergs. Geologic evidence suggests that in the distant past the atmosphere was much denser and water was much more abundant at the surface.
The average temperature in the lower atmosphere is about 200 kelvins (K; -100 °F, -70 °C), which is generally colder than the average daytime surface temperature of 250 K (-10 °F, -20 °C). These values are in the same range as those on Earth in Antarctica during winter. In summer above a very dark surface, daytime temperatures at the height of a human can peak at about 290 K (62 °F, 17 °C). Above the turbulent layer close to the surface, temperature decreases with elevation at a rate of about 1.5 K (2.7 °F, 1.5 °C) per km (about 2.4 K [4.3 °F, 2.4 °C] per mile) of altitude.
Unlike that of Earth, the atmosphere of Mars has large seasonal variations in pressure. During each hemisphere’s winter, the main component, carbon dioxide, “snows out” over the winter pole. And during each hemisphere’s spring, the carbon dioxide returns directly to a gas (sublimes). Because the southern winter cap is larger than the northern, atmospheric pressure reaches a minimum during southern winter when the southern cap is at its largest. From Viking lander measurements of the pressure, which was found to vary by 26 percent annually over the mean, scientists calculated that some 7.9 trillion metric tons of carbon dioxide leave and reenter the atmosphere seasonally. This is equivalent to a thickness of at least 23 cm (9 inches) of solid carbon dioxide (dry ice) or several meters of carbon dioxide snow averaged over the vast area of the seasonal polar caps.
Direct chemical analysis at the surface by the Viking landers and spectral observations from orbiting spacecraft allowed scientists to precisely determine the composition of the atmosphere. Where the atmosphere is well mixed by turbulence—below an altitude of 125 km (about 80 miles)—95.3 percent of the atmosphere by weight is carbon dioxide (see the table). This is a comparatively large amount—nine times the quantity now in Earth's much more massive atmosphere. Much of Earth's carbon dioxide, however, is chemically locked in sedimentary rocks; the amount in the Martian atmosphere is less than a thousandth of the terrestrial total. The balance of the Martian atmosphere consists of molecular nitrogen, water vapor, and noble gases (argon, neon, krypton, and xenon). There are also trace amounts of gases that have been produced from the primary constituents by photochemical reactions, generally high in the atmosphere; these include molecular oxygen, carbon monoxide, nitric oxide, and small amounts of ozone.
The lower atmosphere supplies gas to the planet's ionosphere, where densities are low, temperatures are high, and components separate by diffusion according to their masses. Various constituents in the top of the atmosphere are lost to space, which affects the isotopic composition of the remaining gases. For example, because hydrogen is lost preferentially over its heavier isotope deuterium, Mars's atmosphere contains five times more deuterium than Earth's.
Although water is only a minor constituent of the Martian atmosphere (a few molecules per 10,000 at most), primarily because of low atmospheric and surface temperatures, it plays an important role in atmospheric chemistry and meteorology. The Martian atmosphere is effectively saturated with water vapor, yet there is no liquid water present on the surface. The temperature and pressure of the planet are so low that water molecules can exist only as ice or as vapor. Little water is exchanged daily with the surface despite the very cold nighttime surface temperatures.
Most of the information about atmospheric water on Mars has come from the Viking orbiters, which observed seasonal patterns of water content in the atmosphere over a full Martian year. Water vapor is mixed uniformly up to altitudes of 10–15 km (6–9 miles) and shows strong latitudinal gradients that depend on the season. The largest changes occur in the northern hemisphere. During summer in the north, the complete disappearance of the carbon dioxide cap leaves behind a water-ice cap. Sublimation of water from the residual cap results in a strong north-to-south concentration gradient of water vapor in the atmosphere. In the south, where a small carbon dioxide cap remains in summer and only a small amount of water ice has been detected, a strong water vapor gradient does not normally develop in the atmosphere.
The atmospheric water vapor is thought to be in contact with a much larger reservoir in the Martian soil. Subsurface layers of ice are thought to be ubiquitous on Mars at latitudes between 40° and the poles; the very low subsurface temperatures would prevent the ice from subliming. The 2001 Mars Odyssey spacecraft, which began orbital observations of the planet in late 2001, confirmed that ice is present within a meter of the surface at these latitudes, but it is not known how deep the ice layer extends. In contrast, at low latitudes, ice is unstable, and any ice present in the ground would tend to sublime into the atmosphere.
The Viking landers' analytical instruments also measured the isotopic composition of the major and minor atmospheric gases. The similarity of the ratios of isotopes of carbon and oxygen to their terrestrial values implies that large reservoirs of carbon dioxide and water ice exist on Mars and that gases from the reservoirs exchange with those in the atmosphere. The results of other isotopic measurements from Viking suggest that larger amounts of carbon dioxide, nitrogen, and argon were present in the atmosphere in the past and that Mars may have lost much of its inventory of volatile substances early in its history, either to space or to the ground (i.e., locked up chemically in rocks). Some scientists have conjectured that Mars may once have had a much thicker atmosphere but that it was lost to the surface through chemical reactions, which formed carbonates, and to space through large asteroid impacts, which blew off atmospheric gases.
Next Time: “The Atmosphere, Part 2”
Bibliography
Mars. (2007). In Encyclopædia Britannica. Retrieved October 26, 2007 , from Encyclopædia Britannica Online: http://www.britannica.com/eb/article-9110149
Mars (2007). In The Columbia Encyclopedia, Sixth Edition 2007. Copyright 2007 Columbia University Press. Retrieved October 26, 2007 from Encyclopedia.com
http://www.encyclopedia.com/doc/1E1-Mars-ast.html
Planets: Mars. In NASA Solar System Exploration, Last updated October 23, 2007. Retrieved October 26, 2007, from the NASA Solar System Exploration website, maintained by NASA's Jet Propulsion Laboratory:
http://solarsystem.jpl.nasa.gov/planets/profile.cfm?Object=Mars
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THE SKY THIS WEEK
Nov 17, 5:33 PM EST - First Quarter Moon
Nov 17 - Neptune is 1.0° north of Moon, occultation. An occultation occurs when one object passes in front of a smaller one, temporarily obscuring all or part of the background object from view.
Nov 17 - Leonid meteors
Nov 19 - Uranus is 2° south of Moon
Nov 23 - Moon is at perigee, the point in the Moon's orbit when it is closest from Earth.
Nov 24, 9:30 AM EST - Full Moon. Called the “Beaver Moon” or “Snow Moon,” this was the time to set beaver traps before the swamps froze, in order to ensure a supply of winter furs. Others suggest the name refers to the fact that beavers were actively preparing for winter. This full moon is also sometimes called the “Frosty Moon.”
Nov 24 - Uranus is stationary. The body appears motionless in the sky due to the turning point between its direct and retrograde motion.
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THIS WEEK IN HISTORY
Nov 18, 1989 – Launch of The Cosmic Background Exporer satellite (COBE)
Nov 20, 1889 – Birthday of Edwin Hubble
Nov 20, 2004 - Mars Rover “Spirit” landing on Mars
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MUSICAL DIVERSION
The Dutch folk song "Wilder dan wilt" (Wilder than wild) has been traced back at least to the late 1500s. The song began "Wilder dan wilt, wie sal mij temmen," or "Wilder than wild, who will tame me?" Here are the verses.
Wilder Dan Wilt
Wilder dan wildt, wie sal my temmen,
plach ick te singhen vroech ende laet;
ick heb geluystert na Christi stemmen,
die heeft my getrocken tot anderen staet.
Ick was soo wilt, 't mocht aen my blijcken,
als eenen voghel vliecht in de locht;
Heer Jesus heeft my met sijn practijcken
soo soetkens al in sijn net ghebrocht.
Vry, liber, en los, en onghebonden,
mijn willeken volchde ick over al;
dat heeft my doen vallen in soo veel sonden,
het welck ick met recht beklaghen sal.
Heer Jesus leert my mijn willeken breken,
al vallet my somtijdts hert en swaer;
daer door kan ick veel quaedts versteken,
in alles gherust volgh' ick hem naer.
Ick plach te gaen proncken lancks de straten,
verciert als een goddinneken ient;
heer Jesus heeft my dit doen verlaten,
mijn kruysken opnemen, dat hy my sent.
Cupido begon my heel te minnen
en te bestralen met sijn venijn;
nu leer ick aen Jesum vast leggen mijn sinnen,
om gracy te vinden voor sijn aenschijn.
Voor 't slempen, en dempen, en triomferen,
oock danssen en springhen met herten bly,
moet'ick nu vasten en abstineren;
mijnen tijdt beschreyen, is mijn party.
O Prince, ick wacht mijn recompence,
als ghy sult oordeelen in den troon;
dat ick dan hooren mach die sentence:
‘komt hier mijn bruydt, ontfanght de kroon.’
-----
Some have suggested this was a bawdy song, but a quick scan of the Dutch lyrics and a rough translation here and there will show several references to "Lord Jesus" and "Christ" and "my sin." Such an observation will tell you this was more of a hymn than a tavern song. The tune may be even older than these words. Whatever the case, it seems apparent that the tune was well known because it was later set to other Dutch lyrics. On January 24, 1597 at the Battle of Turnhout, the Dutch Prince Maurice of Orange defeated Spanish occupiers of a region that is now part of the Netherlands. The Dutch Protestants, who had been forbidden to practice their faith under the Catholic King Philip II of Spain, rejoiced through new hymns that celebrated their victory. On such hymn was written by a poet and writer of songs named Adriaen Valéry, who wrote under Latinized name Adrianus Valerius (1575-1625). He actually wrote this new hymn during the year of the Dutch Protestant victory, but it was not widely published until the year after Valéry's death. We can thank his son François for publishing his collecton, entitled "Nederlandtsche Gedenckclanck." The hymn was entitled “Wilt Heden Nu Treden.”
Wilt Heden Nu Treden
Wilt heden nu treden voor God, den Heere,
Hem boven al loven van harte zeer,
En maken groot zijns lieven namens eere,
Die daar nu onzen vijand slaat terneer.
Ter eeren ons Heeren wilt al uw dagen
Dit wonder bijzonder gedenken toch.
Maakt u, o mensch, voor God steeds wel te dragen,
Doet ieder recht en wacht u voor bedrog!
Bidt, waket en maket, dat g'in bekoring
En 't kwade met schade toch niet en valt.
Uw vroomheid brengt den vijand tot verstoring,
Al waar' zijn rijk nog eens zoo sterk bewald!
-----
In 1877, the German chorus master Eduard Kremser (1838-1914) published a translation of the lyrics from Dutch to Latin along with an arrangement of the tune for chorus and orchestra. From that point, the tune became known to many simply as “Kremser.” A few years later, in 1894, the text was loosely translated to English by U.S.-born musical scholar Theodore Baker (1851-1934). Some of the militant flavor of the original was lost, but essence of the text remained. He called the hymn “We Gather Together.”
We Gather Together
We gather together to ask the Lord’s blessing;
He chastens and hastens His will to make known.
The wicked oppressing now cease from distressing.
Sing praises to His Name; He forgets not His own.
Beside us to guide us, our God with us joining,
Ordaining, maintaining His kingdom divine;
So from the beginning the fight we were winning;
Thou, Lord, were at our side, all glory be Thine!
We all do extol Thee, Thou Leader triumphant,
And pray that Thou still our Defender will be.
Let Thy congregation escape tribulation;
Thy Name be ever praised! O Lord, make us free!
-----
This hymn has become for many an important part of their annual Thanksgiving Day celebrations. And then in 1902, J. Archer Gibson, the organist of the Brick Presbyterian Church in New York City, approached active church member Mrs. Julia B. Cory (1882-1963) with a request for a new setting to the tune. For her inspiration, Cory returned to Valéry’s original hymn text. The new hymn was premiered on the very next Thanksgiving Day, and it was first published in “Hymns of the Living Church” in 1910. Cory called her hymn “We Praise Thee, O God, Our Redeemer, Creator.”
We Praise Thee, O God, Our Redeemer, Creator
We praise Thee, O God, our Redeemer, Creator,
In grateful devotion our tribute we bring;
We lay it before Thee, we kneel and adore Thee,
We bless Thy holy Name, glad praises we sing.
We worship Thee, God of our fathers, we bless Thee;
Through life’s storm and tempest our guide have Thou been;
When perils overtake us, escape Thou will make us,
And with Thy help, O Lord, our battles we win.
With voices united our praises we offer,
To Thee, great Jehovah, glad anthems we raise.
Thy strong arm will guide us, our God is beside us,
To Thee, our great Redeemer, forever be praise.
(Cory later added this Christmas stanza)
Thy love Thou didst show us, Thine only Son sending,
Who came as a Babe and Whose bed was a stall,
His blest life He gave us and then died to save us;
We praise Thee, O Lord, for Thy gift to us all.
-----
To view the lyrics of “Wilder Dan Wilt” visit this link - http://www.dbnl.org/tekst/duys001oude03_01/duys001oude03_01_0169.htm
To see and hear more on the hymn, “Wilt Heden Nu Treden” visit this page of "The Cyber Hymnal" - http://www.cyberhymnal.org/non/nl/wilthede.htm
To see and hear more on the hymn, “We Gather Together” visit this page of "The Cyber Hymnal" - http://www.cyberhymnal.org/htm/w/e/wegattog.htm
To see and hear more on the hymn, “We Praise Thee, O God, Our Redeemer, Creator” visit this page of "The Cyber Hymnal" - http://www.cyberhymnal.org/htm/w/p/wptogorc.htm
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Astronomer Questions Significance of COBE Images
Most astronomers say the Cosmic Background Explorer (COBE) satellite images show structures of the early universe. But 70-year-old radio astronomer and author Gerrit Verschuur of the University of Memphis, claims to have evidence that the images actually depict nearby hydrogen gas clouds in our own galaxy, calling into question one of the most important theories in the past 15 years. Verschuur's research will be published December 10 in the Astrophysical Journal.
NASA scientists announced in 1992 that their COBE satellite had imaged the ultimate baby pictures of the universe, revealing the seeds that grew into galaxies like our own Milky Way. And in 2003, higher-resolution images of the seeds were taken by another satellite, the Wilkinson Microwave Anisotropy Probe (WMAP).
According to Verschuur's research, the imaged seeds are located not on the edge of the universe, but nearby. Instead, they're just previously unmapped clouds of "neutral hydrogen" gas located inside the Milky Way. Verschuur sites at least 200 instances where the so-called cosmic seeds lie suspiciously close to known hydrogen clouds inside our galaxy.
Scientists who have reviewed his work suggest Verschuur’s correlations between the WMAP seeds and galactic hydrogen filaments are just coincidences. But as history has shown with previous debates over statistical interpretations, it is likely that Verschuur’s claim will not be settled anytime soon.
To learn more about the Cosmic Background Explorer (COBE) mission, visit the NASA website:
http://lambda.gsfc.nasa.gov/product/cobe/
Wilkinson Microwave Anisotropy Probe (WMAP) mission, visit the NASA website:
http://map.gsfc.nasa.gov/
Hubble Images Do Not Explain Comet 17P/Holmes Outburst
Astronomers are still uncertain what caused the brightening of normally-dim Comet 17P/Holmes, which erupted October 24 and is still shining brightly like a new star in the constellation Perseus.
In a November 15 announcement, three new comet images taken by the Hubble Space Telescope (HST) showed the core of Holmes as a field of particles extending some 15,000 miles across. The images also show that the particles appear to be coming from around the comet's hidden nucleus. This information, combined with another image taken by a ground-based telescope at the Calgary Science Centre (CSC) in Alberta, Canada, supplements the idea of some scientists that something must have broken off from around the nucleus and then disintegrated to become the dust cloud.
According to astronomers, the most likely explanation for the outburst is that a coating of relatively stable water ice, less than 10 miles thick around the comet's nucleus, was suddenly blown away by other, far more volatile chemical ices beneath the frozen water. As those ices heated and expanded violently, they blew the outer ice apart.
The new HST images show no large fragments in the cloud of particles that might suggest they were fragments of the nucleus itself or debris from a collision with a boulder-size asteroid orbiting between Mars and Jupiter - although some astronomers already have proposed that idea.
Seven years ago, HST imaged Comet Holmes, then nearly 150 million miles away. Astronomers inferred from the comet's brightness that its nucleus of rock and ice was barely more than 2 miles wide and that no dust obscured it. But the three new HST images have identified the 15,000-mile core of particles closest to the nucleus.
In addition, the new CSC image shows that at its brightest, the comet's particles extend for at least 2 million miles, with a thinner scattering of particles on its lower right side that may be the beginning of a comet tail.
When British amateur astronomer Edwin Holmes discovered the comet in November of 1892, he detected it because it had suddenly burst into a huge ball of light in his telescope. It then dimmed and, 73 days later, flared up briefly again.
At the time, U.S. astronomer Fred Whipple suggested that the flare-ups occurred because the comet had a double nucleus. Whipple proposed that one nucleus hit the other in a "grazing collision" that triggered the comet's first brilliant cloud of gas and dust, and then a full head-on crash 73 days later created the spectacular second outburst. In recalling Holmes' discovery, some will be watching in mid-January, hoping for a second display.
Still others suggest this year's flare-up might have resulted from a fragile nucleus spinning so fast that it just flew apart.
Astronomers at the Space Telescope Science Institute are studying the feasibility of a 2015 NASA mission to Comet Holmes or some other comet that has a history of flare-ups, and to orbit it long enough to learn the cause and maybe return a sample of the particles.
To learn more, visit Hubble Site, home of NASA's Hubble Space Telescope: http://hubblesite.org/
To learn more about the Calgary Science Centre in Alberta, Canada, visit their website: http://www.calgaryscience.ca/
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MARS IS COMING, PART 3
As the December 24 opposition approaches, please enjoy this third installment on the Red Planet Mars.
The Atmosphere (Part 1)
In 1947, Dutch-American astronomer Gerard P. Kuiper (1905-1973) determined from telescopic observations that the Martian atmosphere is composed mainly of carbon dioxide. The atmosphere is very thin, pushing at less than 1 percent of Earth's atmospheric pressure at the surface. The altitude varies greatly over the Martian surface, causing surface pressures to range over a factor of 15. Today's atmosphere has only small amounts of water. If it all was extracted and frozen, it would form a layer of ice crystals only 10 micrometers (0.0004 inch) thick, which could be gathered into a solid block of ice not much larger than one of Earth's medium-size icebergs. Geologic evidence suggests that in the distant past the atmosphere was much denser and water was much more abundant at the surface.
The average temperature in the lower atmosphere is about 200 kelvins (K; -100 °F, -70 °C), which is generally colder than the average daytime surface temperature of 250 K (-10 °F, -20 °C). These values are in the same range as those on Earth in Antarctica during winter. In summer above a very dark surface, daytime temperatures at the height of a human can peak at about 290 K (62 °F, 17 °C). Above the turbulent layer close to the surface, temperature decreases with elevation at a rate of about 1.5 K (2.7 °F, 1.5 °C) per km (about 2.4 K [4.3 °F, 2.4 °C] per mile) of altitude.
Unlike that of Earth, the atmosphere of Mars has large seasonal variations in pressure. During each hemisphere’s winter, the main component, carbon dioxide, “snows out” over the winter pole. And during each hemisphere’s spring, the carbon dioxide returns directly to a gas (sublimes). Because the southern winter cap is larger than the northern, atmospheric pressure reaches a minimum during southern winter when the southern cap is at its largest. From Viking lander measurements of the pressure, which was found to vary by 26 percent annually over the mean, scientists calculated that some 7.9 trillion metric tons of carbon dioxide leave and reenter the atmosphere seasonally. This is equivalent to a thickness of at least 23 cm (9 inches) of solid carbon dioxide (dry ice) or several meters of carbon dioxide snow averaged over the vast area of the seasonal polar caps.
Direct chemical analysis at the surface by the Viking landers and spectral observations from orbiting spacecraft allowed scientists to precisely determine the composition of the atmosphere. Where the atmosphere is well mixed by turbulence—below an altitude of 125 km (about 80 miles)—95.3 percent of the atmosphere by weight is carbon dioxide (see the table). This is a comparatively large amount—nine times the quantity now in Earth's much more massive atmosphere. Much of Earth's carbon dioxide, however, is chemically locked in sedimentary rocks; the amount in the Martian atmosphere is less than a thousandth of the terrestrial total. The balance of the Martian atmosphere consists of molecular nitrogen, water vapor, and noble gases (argon, neon, krypton, and xenon). There are also trace amounts of gases that have been produced from the primary constituents by photochemical reactions, generally high in the atmosphere; these include molecular oxygen, carbon monoxide, nitric oxide, and small amounts of ozone.
The lower atmosphere supplies gas to the planet's ionosphere, where densities are low, temperatures are high, and components separate by diffusion according to their masses. Various constituents in the top of the atmosphere are lost to space, which affects the isotopic composition of the remaining gases. For example, because hydrogen is lost preferentially over its heavier isotope deuterium, Mars's atmosphere contains five times more deuterium than Earth's.
Although water is only a minor constituent of the Martian atmosphere (a few molecules per 10,000 at most), primarily because of low atmospheric and surface temperatures, it plays an important role in atmospheric chemistry and meteorology. The Martian atmosphere is effectively saturated with water vapor, yet there is no liquid water present on the surface. The temperature and pressure of the planet are so low that water molecules can exist only as ice or as vapor. Little water is exchanged daily with the surface despite the very cold nighttime surface temperatures.
Most of the information about atmospheric water on Mars has come from the Viking orbiters, which observed seasonal patterns of water content in the atmosphere over a full Martian year. Water vapor is mixed uniformly up to altitudes of 10–15 km (6–9 miles) and shows strong latitudinal gradients that depend on the season. The largest changes occur in the northern hemisphere. During summer in the north, the complete disappearance of the carbon dioxide cap leaves behind a water-ice cap. Sublimation of water from the residual cap results in a strong north-to-south concentration gradient of water vapor in the atmosphere. In the south, where a small carbon dioxide cap remains in summer and only a small amount of water ice has been detected, a strong water vapor gradient does not normally develop in the atmosphere.
The atmospheric water vapor is thought to be in contact with a much larger reservoir in the Martian soil. Subsurface layers of ice are thought to be ubiquitous on Mars at latitudes between 40° and the poles; the very low subsurface temperatures would prevent the ice from subliming. The 2001 Mars Odyssey spacecraft, which began orbital observations of the planet in late 2001, confirmed that ice is present within a meter of the surface at these latitudes, but it is not known how deep the ice layer extends. In contrast, at low latitudes, ice is unstable, and any ice present in the ground would tend to sublime into the atmosphere.
The Viking landers' analytical instruments also measured the isotopic composition of the major and minor atmospheric gases. The similarity of the ratios of isotopes of carbon and oxygen to their terrestrial values implies that large reservoirs of carbon dioxide and water ice exist on Mars and that gases from the reservoirs exchange with those in the atmosphere. The results of other isotopic measurements from Viking suggest that larger amounts of carbon dioxide, nitrogen, and argon were present in the atmosphere in the past and that Mars may have lost much of its inventory of volatile substances early in its history, either to space or to the ground (i.e., locked up chemically in rocks). Some scientists have conjectured that Mars may once have had a much thicker atmosphere but that it was lost to the surface through chemical reactions, which formed carbonates, and to space through large asteroid impacts, which blew off atmospheric gases.
Next Time: “The Atmosphere, Part 2”
Bibliography
Mars. (2007). In Encyclopædia Britannica. Retrieved October 26, 2007 , from Encyclopædia Britannica Online: http://www.britannica.com/eb/article-9110149
Mars (2007). In The Columbia Encyclopedia, Sixth Edition 2007. Copyright 2007 Columbia University Press. Retrieved October 26, 2007 from Encyclopedia.com
http://www.encyclopedia.com/doc/1E1-Mars-ast.html
Planets: Mars. In NASA Solar System Exploration, Last updated October 23, 2007. Retrieved October 26, 2007, from the NASA Solar System Exploration website, maintained by NASA's Jet Propulsion Laboratory:
http://solarsystem.jpl.nasa.gov/planets/profile.cfm?Object=Mars
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THE SKY THIS WEEK
Nov 17, 5:33 PM EST - First Quarter Moon
Nov 17 - Neptune is 1.0° north of Moon, occultation. An occultation occurs when one object passes in front of a smaller one, temporarily obscuring all or part of the background object from view.
Nov 17 - Leonid meteors
Nov 19 - Uranus is 2° south of Moon
Nov 23 - Moon is at perigee, the point in the Moon's orbit when it is closest from Earth.
Nov 24, 9:30 AM EST - Full Moon. Called the “Beaver Moon” or “Snow Moon,” this was the time to set beaver traps before the swamps froze, in order to ensure a supply of winter furs. Others suggest the name refers to the fact that beavers were actively preparing for winter. This full moon is also sometimes called the “Frosty Moon.”
Nov 24 - Uranus is stationary. The body appears motionless in the sky due to the turning point between its direct and retrograde motion.
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THIS WEEK IN HISTORY
Nov 18, 1989 – Launch of The Cosmic Background Exporer satellite (COBE)
Nov 20, 1889 – Birthday of Edwin Hubble
Nov 20, 2004 - Mars Rover “Spirit” landing on Mars
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MUSICAL DIVERSION
The Dutch folk song "Wilder dan wilt" (Wilder than wild) has been traced back at least to the late 1500s. The song began "Wilder dan wilt, wie sal mij temmen," or "Wilder than wild, who will tame me?" Here are the verses.
Wilder Dan Wilt
Wilder dan wildt, wie sal my temmen,
plach ick te singhen vroech ende laet;
ick heb geluystert na Christi stemmen,
die heeft my getrocken tot anderen staet.
Ick was soo wilt, 't mocht aen my blijcken,
als eenen voghel vliecht in de locht;
Heer Jesus heeft my met sijn practijcken
soo soetkens al in sijn net ghebrocht.
Vry, liber, en los, en onghebonden,
mijn willeken volchde ick over al;
dat heeft my doen vallen in soo veel sonden,
het welck ick met recht beklaghen sal.
Heer Jesus leert my mijn willeken breken,
al vallet my somtijdts hert en swaer;
daer door kan ick veel quaedts versteken,
in alles gherust volgh' ick hem naer.
Ick plach te gaen proncken lancks de straten,
verciert als een goddinneken ient;
heer Jesus heeft my dit doen verlaten,
mijn kruysken opnemen, dat hy my sent.
Cupido begon my heel te minnen
en te bestralen met sijn venijn;
nu leer ick aen Jesum vast leggen mijn sinnen,
om gracy te vinden voor sijn aenschijn.
Voor 't slempen, en dempen, en triomferen,
oock danssen en springhen met herten bly,
moet'ick nu vasten en abstineren;
mijnen tijdt beschreyen, is mijn party.
O Prince, ick wacht mijn recompence,
als ghy sult oordeelen in den troon;
dat ick dan hooren mach die sentence:
‘komt hier mijn bruydt, ontfanght de kroon.’
-----
Some have suggested this was a bawdy song, but a quick scan of the Dutch lyrics and a rough translation here and there will show several references to "Lord Jesus" and "Christ" and "my sin." Such an observation will tell you this was more of a hymn than a tavern song. The tune may be even older than these words. Whatever the case, it seems apparent that the tune was well known because it was later set to other Dutch lyrics. On January 24, 1597 at the Battle of Turnhout, the Dutch Prince Maurice of Orange defeated Spanish occupiers of a region that is now part of the Netherlands. The Dutch Protestants, who had been forbidden to practice their faith under the Catholic King Philip II of Spain, rejoiced through new hymns that celebrated their victory. On such hymn was written by a poet and writer of songs named Adriaen Valéry, who wrote under Latinized name Adrianus Valerius (1575-1625). He actually wrote this new hymn during the year of the Dutch Protestant victory, but it was not widely published until the year after Valéry's death. We can thank his son François for publishing his collecton, entitled "Nederlandtsche Gedenckclanck." The hymn was entitled “Wilt Heden Nu Treden.”
Wilt Heden Nu Treden
Wilt heden nu treden voor God, den Heere,
Hem boven al loven van harte zeer,
En maken groot zijns lieven namens eere,
Die daar nu onzen vijand slaat terneer.
Ter eeren ons Heeren wilt al uw dagen
Dit wonder bijzonder gedenken toch.
Maakt u, o mensch, voor God steeds wel te dragen,
Doet ieder recht en wacht u voor bedrog!
Bidt, waket en maket, dat g'in bekoring
En 't kwade met schade toch niet en valt.
Uw vroomheid brengt den vijand tot verstoring,
Al waar' zijn rijk nog eens zoo sterk bewald!
-----
In 1877, the German chorus master Eduard Kremser (1838-1914) published a translation of the lyrics from Dutch to Latin along with an arrangement of the tune for chorus and orchestra. From that point, the tune became known to many simply as “Kremser.” A few years later, in 1894, the text was loosely translated to English by U.S.-born musical scholar Theodore Baker (1851-1934). Some of the militant flavor of the original was lost, but essence of the text remained. He called the hymn “We Gather Together.”
We Gather Together
We gather together to ask the Lord’s blessing;
He chastens and hastens His will to make known.
The wicked oppressing now cease from distressing.
Sing praises to His Name; He forgets not His own.
Beside us to guide us, our God with us joining,
Ordaining, maintaining His kingdom divine;
So from the beginning the fight we were winning;
Thou, Lord, were at our side, all glory be Thine!
We all do extol Thee, Thou Leader triumphant,
And pray that Thou still our Defender will be.
Let Thy congregation escape tribulation;
Thy Name be ever praised! O Lord, make us free!
-----
This hymn has become for many an important part of their annual Thanksgiving Day celebrations. And then in 1902, J. Archer Gibson, the organist of the Brick Presbyterian Church in New York City, approached active church member Mrs. Julia B. Cory (1882-1963) with a request for a new setting to the tune. For her inspiration, Cory returned to Valéry’s original hymn text. The new hymn was premiered on the very next Thanksgiving Day, and it was first published in “Hymns of the Living Church” in 1910. Cory called her hymn “We Praise Thee, O God, Our Redeemer, Creator.”
We Praise Thee, O God, Our Redeemer, Creator
We praise Thee, O God, our Redeemer, Creator,
In grateful devotion our tribute we bring;
We lay it before Thee, we kneel and adore Thee,
We bless Thy holy Name, glad praises we sing.
We worship Thee, God of our fathers, we bless Thee;
Through life’s storm and tempest our guide have Thou been;
When perils overtake us, escape Thou will make us,
And with Thy help, O Lord, our battles we win.
With voices united our praises we offer,
To Thee, great Jehovah, glad anthems we raise.
Thy strong arm will guide us, our God is beside us,
To Thee, our great Redeemer, forever be praise.
(Cory later added this Christmas stanza)
Thy love Thou didst show us, Thine only Son sending,
Who came as a Babe and Whose bed was a stall,
His blest life He gave us and then died to save us;
We praise Thee, O Lord, for Thy gift to us all.
-----
To view the lyrics of “Wilder Dan Wilt” visit this link - http://www.dbnl.org/tekst/duys001oude03_01/duys001oude03_01_0169.htm
To see and hear more on the hymn, “Wilt Heden Nu Treden” visit this page of "The Cyber Hymnal" - http://www.cyberhymnal.org/non/nl/wilthede.htm
To see and hear more on the hymn, “We Gather Together” visit this page of "The Cyber Hymnal" - http://www.cyberhymnal.org/htm/w/e/wegattog.htm
To see and hear more on the hymn, “We Praise Thee, O God, Our Redeemer, Creator” visit this page of "The Cyber Hymnal" - http://www.cyberhymnal.org/htm/w/p/wptogorc.htm
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Saturday, November 10, 2007
Comet 17P/Holmes Still Amazing Us
Now that a cold front has given central Florida back its nighttime sky, at least for a few evenings, this would be the perfect time to check out amazing Comet 17P/Holmes. In the early morning of October 24, Spanish amateur astronomer Juan Santana noticed that normally dim Comet 17P/Holmes had brightened considerably from observations made on previous nights. The sudden million-fold increase in brightness allowed the comet to become visible to the naked eye. The comet's coma, or outer cloud of gas and dust, is now physically much larger than the planet Jupiter.
It was just such an eruption of gas and dust that allowed the comet to be discovered in November of 1892 by English amateur astronomer Edwin Holmes. This is an excellent imaging target for off-the-shelf digital cameras and backyard telescopes.
The comet is still located just to the East (left) of the constellation Perseus. If you are in the Tampa Bay area, Perseus will rise in the North East and be completely above the horizon after 7PM EST. Comet 17P/Holmes should be visible roughly one-third of the way between Mirfak, the brightest star in Perseus, and the first magnitude wintertime star Capella, the brightest star in the constellation Auriga.
BACKGROUND: Comet 17P/Holmes was discovered by British amateur astronomer Edwin Holmes (1842-1919) on November 6, 1892 while conducting regular observations of the Andromeda Galaxy (M31). The orbital specifics for the comet are as follows: Aphelion distance, 5.2004 AU; Perihelion distance, 2.1655 AU; Semi-major axis, 3.618 AU ; Eccentricity, 0.4120; Orbital period, 7.0679 a (Julian years, lasting 362.25 days); Inclination, 19.1877°; Last perihelion, May 4, 2007; Next perihelion (predicted), March 27, 2014.
For more details and new information, check out these Web pages:
Space Weather Home Page:
http://spaceweather.com/
Space Weather Sky Chart:
http://spaceweather.com/images2007/24oct07/skymap_north_holmes.gif?PHPSESSID=ctmhv5tmpkfnk942ajcl3k17o7
Sky and Telescope Article:
http://www.skyandtelescope.com/observing/home/10862521.html
Phoenix Tilts Its Wings
On November 6, NASA's Phoenix Mars Lander mission team performed a spacecraft orientation adjustment to allow its solar panels to receive more energy from the sun.
During the first three months of the University of Arizona-led mission, which launched August 4, the spacecraft's solar panels were not pointed directly at the sun. If they had, the closer proximity to the sun would have overwhelmed the spacecraft's electrical systems.
With the spacecraft having covered 165 million miles of its 423 million mile journey to Mars, it receives less power as its distance from the sun increases.
The spacecraft also recently did a second trajectory correction maneuver that put it on course to be captured by the Martian gravitation field as it nears the planet. The spacecraft's original course was set from launch so that it would avoid hitting the planet if control problems arose. Additional trajectory corrections are scheduled for April and May to fine-tune the spacecraft's path to its landing site.
The lander is slated to arrive on Mars May 25. The Phoenix mission will look for evidence of water and the elements of life on Mars. It will analyze soil and ice samples scooped from the planet's northern arctic region.
The $420 million mission is led by University of Arizona, the first public institution to lead a mission to Mars. To learn more, visit the mission home page: http://phoenix.lpl.arizona.edu/
Five-Planet Star System Discovered
On November 06, NASA scientists announced the discovery of a record-setting fifth planet discovered orbiting a single star. The discovery suggests that multi-planet systems such as ours may not be unusual.
The star is the sunlike 55 Cancri, located 41 light-years away in the constellation Cancer. Researchers describe the new planet as a "mini-Saturn" of about 46 Earth masses. It is the fourth out from the star in a large gap between the third and fifth planets, placing it in the estimated habitable zone around the star where water might remain liquid.
The planet's size implies that it is a Jovian-like planet of hydrogen and helium gas, but the finding raises the possibility that earthlike moons might be orbiting the planet.
55 Cancri's system of five planets all seem to orbit along relatively circular paths, and the farthest planet out, a gaseous super-giant the size of four Jupiters, orbits at roughly the same distance from its star as the the distance of our Jupiter from the sun.
55 Cancri's innermost planet, weighing in at more than 10 earth masses—meaning it could have a rocky or icy core—lies closer to its star than Mercury does to our own. The new planet sits at 0.8 earth-sun distances (astronomical units) from the star, or roughly the distance between Venus and the sun. Before this discovery, researchers knew of only one other four-planet system, Mu Arae, and several three-planet systems.
55 Cancri system is one of many stars that for 18 years have been carefully and regularly measured by California's Lick Observatory and Hawaii's Keck Telescope. Researchers looked at the star's Doppler shift--the change in the wavelength, or color, of its light as it moved toward and away from Earth. A star tugged by an orbiting planet will wobble slightly, which can be detected as a regular shift in the star's color corresponding to the time the planet requires to complete an orbit. For example, 55 Cancri's outer planet has an orbital period of 14 years, and so was not discovered until 2004.
The research team's report has been accepted for future publication in The Astrophysical Journal. To learn more about the discovery and the observatories participating in the research, check these links:
University of California Observatories, Lick Observatory:
http://www.ucolick.org/
W. M. Keck Observatory:
http://www.keckobservatory.org/
Leonid Meteors Return
November 17 marks the peak of the annual Leonid meteor shower. Meteors from this shower may be visible from Nov. 15 through Nov. 20. Leonid meteors have an entry velocity of 71 km/second and glow with a bluish-green tint. This shower is caused by Periodic Comet 55P/Tempel-Tuttle, which returns to the inner solar system every 32.9 years. Meteor hourly rates are irregular and may reach 40 or greater in years surrounding the return of the comet. But since that last occurred in 1999, we can probably expect a rate of 10 to 15 per hour. The best chances to see Leonids are in the early morning hours during the days surrounding the peak (Nov. 16, 17, 18). The meteors will appear to originate from a point in the constellation of Leo (RA 10hrs 08min, Dec +22°).
The Leonids played a great role in our understanding of meteor showers. The great meteor storm of November 12-13, 1833 is regarded as the date of the birth of meteor astronomy. Following that meteor storm, Professors Olmsted and Twining of then Yale College pointed out that the meteors appeared to radiate from a point in the constellation Leo, the Lion. The fact that the meteors radiated from a single point indicated that they were all part of a swarm of meteoroids moving in the same orbital path. Later, Professor Hubert Anson Newton (1830-1896) an astronomer and mathematician who was also of Yale College, calculated that the orbit had a period of 33 years and used records to trace appearances of the shower as far back as AD 902. He also observed that the time of the Leonid shower moved along the calendar at the rate of about a month in a hundred years. Newton then successfully predicted the appearance of the 1866 Leonid storm. A few weeks after the 1866 storm astronomers found that the orbit of the meteoroid stream was identical with Temple's Comet, seen a year earlier. About this same time Italian astronomer Giovanni Schiaparelli (1835-1910) showed that the Perseid meteors came from a stream that moved in an orbit identical to the bright comet of 1862. These were the first observations to connect comets with the fall meteor showers.
There is historical evidence that Abraham Lincoln (1809-1865) also witnessed the great Leonid meteor storm of 1833 as a young man of 24. According to cross-referenced records and personal journals, Lincoln was apparently in New Salem, Illinois staying at the Rutledge Tavern, a log cabin then owned by Henry Onstot, a cooper by trade (bucket and barrel maker) and member of the Cumberland Presbyterian Church. Lincoln recounted the story in the presence of American writer Walt Whitman (1819-1892) who was a frequent guest of the Lincoln White House. Whitman later published the story in his book "Specimen Days & Collect," published in 1882. When asked by another White House guest whether the Union would survive the ongoing Civil War, Whitman noted that Lincoln, ever the story-teller, replied with this story. "When I was a young man in Illinois," said he, "I boarded for a time with a Deacon of the Presbyterian church. One night I was roused from my sleep by a rap at the door, & I heard the Deacon's voice exclaiming 'Arise, Abraham, the day of judgement has come!' I sprang from my bed & rushed to the window, and saw the stars falling in great showers! But looking back of them in the heavens I saw all the grand old constellations with which I was so well acquainted, fixed and true in their places. Gentlemen, the world did not come to an end then, nor will the Union now."
Thank Yous
Thanks to MARS member James Dagget who, following our report on quasars in early galaxies, shared his memories of working in the Quasar TV plant in Plantation, Florida the 1970s. James knows better than most about the inconsistent "quality" that went into those sets before the name went on.
Thanks to MARS member Craig MacDougal for sharing his backyard binocular observation of Comet 17P/Holmes during an all-too-brief break in the cloud cover last week. At that time the comet shone brighter than second magnitude and still continues to impress us now.
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MARS IS COMING, PART 2
As we prepare for the December 24 opposition, please enjoy this next installment on the Red Planet Mars.
Early Observations
Mars was a puzzle to ancient astronomers. They did not understand why it sometimes moved through the sky in the same direction as the sun and other celestial objects (direct, or prograde, motion), and sometimes moved in the opposite direction (retrograde motion). In 1609 the German mathematician and astronomer Johannes Kepler (1571-1630) used the excellent naked-eye observations of Danish astronomer Tycho Brahe (1546-1601) to deduce empirically the laws of motion for Mars and so pave the way for the modern gravitational theory of the solar system. Rather than having a circular orbit with uniform motion, as suggested by earlier Ptolemy-inspired theories, Kepler found that the orbit of Mars was an ellipse along which the planet moved with non-uniform but predictable motion--faster when closer to the sun, slower when farther away.
The earliest telescopic observations of Mars were made in 1610 by Italian astronomer Galileo Galilei (1564-1642) . This was also the first time that Mars was clearly seen not as a point of light, but as a disk. The Dutch scientist and mathematician Christiaan Huygens (1629-1695) is credited with the first accurate drawings of the planet's surface markings. In 1659 Huygens made a drawing that showed a major dark marking that is now known as Syrtis Major. About 1666, the Martian polar caps were first noted by the Italian-born French astronomer Gian Domenico Cassini (1625-1712).
Many key discoveries were made by visual observers. In 1659, Huygens discovered that Mars rotates and, in 1666, measured that rotation to be 24 hours 40 minutes--over today’s measurement by only 3 minutes. In the 1780s, German-born British astronomer William Herschel (1738-1822) first noted the very thin Martian atmosphere, and Herschel also measured the tilt of the planet's rotation axis and first discussed the Martian seasons. In 1877 the U.S. Naval Observatory's Asaph Hall (1829-1907) discovered that Mars has two natural satellites. Visual observers also documented many meteorological and seasonal changes that occur on Mars, such as various cloud types, the growing and shrinking of the polar caps, changes in the color and size of the dark areas, an annual "wave of darkening" in the markings that sweeps across the planet in time with the shrinking of the polar caps, and an occasional "blue haze" in the atmosphere. Most of these events were not explained until Mars was visited by spacecraft.
Visible Surface Features
Aside from the white polar caps, Earth-based telescopes show Mars generally to have a bright red-orange-colored surface that is covered by dark markings. Originally, the bright areas were called deserts, and most of the large dark areas were called maria (Latin, meaning "oceans" or "seas") because observers once thought the dark areas were covered by water.
The dark markings cover about one-third of the surface, mostly in a band around the planet between latitudes 10° and 40° South. They are irregularly distributed, and their overall pattern can change over many years. The northern hemisphere has only three major dark features. One is called Acidalia Planitia, another is called Syrtis Major, and the third is a dark collar around the northern pole. These were once thought to be shallow seas or areas of vegetation. We now know that Mars' dark areas form and change as the winds move surface material. Images from orbiting spacecraft reveal that the dark areas are actually collections of many dark streaks and splotches that are associated with craters, ridges, hills, and other geologic features that can block the local winds.
The bright areas, which cover about two-thirds of the surface, have subtle shadings, but these probably also are the result of the winds moving surface material. Beginning in 1877 with Italian astronomer Giovanni Schiaparelli (1835-1910) and into the early 20th century, maps of Mars showed many canals or channels—thin lines connecting the darker surface markings and thought by some at the time to be transportation for agricultural irrigation. However, these markings were not seen later in the images taken by flyby and orbiting spacecraft. The canals were apparently features that observers thought they saw while trying to push the resolution limits of their telescopes. Other features, such as the "wave of darkening" and the "blue haze" described by early telescopic observers, are now known to result from a combination of the viewing conditions and changes in the reflective properties of the surface.
For telescopic observers, the most dramatic regular changes on Mars occur at the poles. As fall begins in a particular hemisphere, clouds develop over that polar region, and the cap, made of frozen carbon dioxide, begins to grow. The smaller cap in the north can extend to 55° latitude, the larger cap in the south can extend to 50° latitude. In spring the caps recede. During northern summer the northern carbon dioxide cap disappears completely, leaving behind a small water-ice cap. And during the southern summer there is a small residual cap composed of carbon dioxide ice and water ice.
Early telescopic observers noted times when Martian surface features were temporarily hidden. They generally thought these were caused by white clouds or yellow clouds, and they interpreted the white clouds to be gas and the yellow clouds to be dust. Spacecraft images have since confirmed these interpretations were correct, and that hazes, clouds, and fogs regularly hide the surface.
Images from spacecraft in Mars orbit have found a variety of low-lying clouds and fogs, often in topographic depressions such as valleys or craters. They have also revealed high, thin clouds, particularly at the terminator--the dividing line between the daytime and nighttime portions of the planet's observable disk. Orographic clouds, which are produced when moist air is lifted over elevated terrain and cooled, form around prominent topographic features such as craters and volcanoes. Winter at the middle latitudes is characterized by westward-moving, spiral-shaped storm systems that are similar to those on Earth. Most of these clouds are composed of water ice--the white clouds that were seen by the early telescopic observers.
Dust storms are common on Mars. They can occur at any time but are most frequent in southern spring and summer, when Mars is passing closest to the sun and surface temperatures are at their highest. Most of the storms are regional in extent and last a few weeks. But every two or three years, the dust storms become global. At their peak, dust is carried so high in the atmosphere that only the summits of the tallest volcanoes--up to 21 km (13 miles) above the planet's mean radius--are visible. Although too small to be observed from Earth, the small sand tornados, called dust devils, have been seen by spacecraft in Mars orbit and by surface craft such as Mars Pathfinder and the Mars Exploration Rovers.
Next time: "The Martian Atmosphere"
Bibliography
Mars. (2007). In Encyclopædia Britannica. Retrieved October 26, 2007 , from Encyclopædia Britannica Online: http://www.britannica.com/eb/article-9110149
Mars (2007). In The Columbia Encyclopedia, Sixth Edition 2007. Copyright 2007 Columbia University Press. Retrieved October 26, 2007 from Encyclopedia.com
http://www.encyclopedia.com/doc/1E1-Mars-ast.html
Planets: Mars. In NASA Solar System Exploration, Last updated October 23, 2007. Retrieved October 26, 2007, from the NASA Solar System Exploration website, maintained by NASA's Jet Propulsion Laboratory:
http://solarsystem.jpl.nasa.gov/planets/profile.cfm?Object=Mars
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THE SKY THIS WEEK
Nov 11 - Dwarf Planet Ceres is at opposition (7.2 Magnitude)
Nov 11 – the star Antares is 0.4° north of the moon, occultation. An occultation occurs when one object passes in front of a smaller one, temporarily obscuring all or part of the background object from view.
Nov 12 – Jupiter is 5° north of the moon
Nov 12 - Dwarf Planet Ceres at its closest approach to Earth (1.832 AU)
Nov 14 – Asteroid Juno is in conjunction with the sun
Nov 15 - Mars is stationary. The body appears motionless in the sky due to the turning point between its direct and retrograde motion.
Nov 17, 5:33 P.M. EST - First Quarter Moon
Nov 17 - Neptune is 1.0° north of the moon, occultation. An occultation occurs when one object passes in front of a smaller one, temporarily obscuring all or part of the background object from view.
Nov 17 – the moon occults the planet Neptune
Nov 17 - Leonid Meteor Shower Peak
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THIS WEEK IN HISTORY
Nov 11, 1572 - Tycho Brahe's Discovery of a supernova, SN1572, 435th anniversary
Nov 11, 1875 - Vesto Slipher's birthday
Nov 11, 1966 - Gemini 12 launch (Jim Lovell and Buzz Aldrin)
Nov 12, 1891 - Seth Nicholson's birthday
Nov 12, 1924 - Audouin Dollfus' birthday
Nov 12, 1980 - Voyager 1, Saturn Flyby
Nov 13, 1831 - James Clerk Maxwell's birthday
Nov 14, 1969 - Apollo 12 Launch (Manned Moon Mission)
Nov 14, 1971 - Mariner 9, Mars Orbit Insertion
Nov 16, 2001 - Genesis, L1 Orbit Insertion
Nov 17, 1597 - Henry Gellibrand's 410th Birthday
Nov 17, 1966 – Leonid Meteor Storm
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MUSICAL DIVERSION
The song called "The Girl I Left Behind Me" has much folklore associated with it. Some say the song’s tune was popular as far back as the reign of Queen Elizabeth I, and that it was regularly played when regiments left town or when man-of-war ships set sail.
One source reports that the tune was known in America as early as 1650 and that it was a traditional fife tune, imported from England as "Brighten Camp." The tune became generally popular during the American Revolution. The tune was known in Ireland as "The Rambling Laborer" and "The Spailpin Fanach" and was first published in Dublin in 1791.
The tune is easy to play on the fife--a small flute. This song, along with “Yankee Doodle,” is often associated with the famous painting called “The Spirit of ’76.”
There are many settings for this tune. Below are two version of “The Girl I Left Behind Me.” The first comes from a collection called “Songs of the Seventh Calvary.” The origin of the other version is not certain. A third song based on this tune follows them.
The Girl I Left Behind Me
(from “Songs of the Seventh Calvary”)
The hours sad I left a maid
A lingering farewell taking
Whose sighs and tears my steps delayed
I thought her heart was breaking
In hurried words her name I blest
I breathed the vows that bind me
And to my heart in anguish pressed
The girl I left behind me
Then to the east we bore away
To win a name in story
And there where dawns the sun of day
There dawned our sun of glory
The place in my sight
When in the host assigned me
I shared the glory of that fight
Sweet girl I left behind me
Though many a name our banner bore
Of former deeds of daring
But they were of the day of yore
In which we had no sharing
But now our laurels freshly won
With the old one shall entwine me
Singing worthy of our size each son
Sweet girl I left behind me
The hope of final victory
Within my bosom burning
Is mingling with sweet thoughts of thee
And of my fond returning
But should I n'eer return again
Still with thy love i'll bind me
Dishonors breath shall never stain
The name I leave behind me
-----
The Girl I Left Behind Me
(an alternate version)
I'm lonesome since I crossed the hill,
And o'er the moorland sedgy
Such heavy thoughts my heart do fill,
Since parting with my Betsey
I seek for one as fair and gay,
But find none to remind me
How sweet the hours I passed away,
With the girl I left behind me.
O ne'er shall I foget the night,
the stars were bright above me
And gently lent their silv'ry light
when first she vowed to love me
But now I'm bound to Brighton camp
kind heaven then pray guide me
And send me safely back again,
to the girl I left behind me
Her golden hair in ringlets fair,
her eyes like diamonds shining
Her slender waist, her heavenly face,
that leaves my heart still pining
Ye gods above oh hear my prayer
to my beauteous fair to find me
And send me safely back again,
to the girl I left behind me
The bee shall honey taste no more,
the dove become a ranger
The falling waters cease to roar,
ere I shall seek to change her
The vows we made to heav'n above
shall ever cheer and bind me
In constancy to her I love,
the girl I left behind me.
-----
"Waxie's Dargle" is an old drinking song that is set to the same tune. Waxies were candlemakers, traditionally women, and "dargle" was a term for their annual working trip to Bray in Ireland. The River Dargle begins up in the Wicklow Mountains and finally empties into Irish Sea in Bray Harbor. Another source says the Dargle (a popular pub) was also a holiday haunt of the late eighteenth century Dublin candlemaker and grocer, Waxy O'Connor.
Here are some translations for the lyrics. “Auld one,” or old one, means wife. “Auld lad,” or old lad, means husband. In some versions the word “Uncle” is substituted with the phrase "Young Kill."
Waxie's Dargle
Says my auld one to your auld one
Will you come to the Waxie's dargle
Says your auld one to my auld one
Sure I haven't got a farthing
I've just been down to Monto town
To see Uncle McArdle
But he wouldn't lend me a half a crown
To go to the Waxie's dargle
Chorus:
What'll you have, will you have a pint
Yes, I'll have a pint with you, sir
And if one of us doesn't order soon
We'll be thrown out of the boozer
Says my auld one to your auld one
Will you come to the Galway races
Says your auld one to my auld one
With the price of my auld lad's braces
I went down to Capel Street
To the pawn shop money lenders
But they wouldn't give me a couple of bob
On my auld lad's red suspenders
(chorus)
Says my auld one to your auld one
We've got no beef nor mutton
But if we go down to Monto town
We might get a drink for nothin'
Here's a piece of good advice
I got from an auld fish-monger
When food is scarce and you see the hearse
You'll know you've died of hunger
(chorus)
-----
To review some the history, the text, or to listen to the melody, check out this pages from the "Songs of England" section of "Contemplations from the Marianas Trench - Music and Deep Thoughts"
- (The Girl I left Behind Me, Version 1) http://www.contemplator.com/england/girl.html
- (The Girl I left Behind Me, Version 2) http://www.contemplator.com/england/girl2.html
- (Waxie's Dargle) http://www.contemplator.com/england/waxie.html
To see a GIF image file of the score of the song, or to download an ABC file of the score, or other notations, visit this mirror site of Digital Tradition - http://sniff.numachi.com/pages/tiGIRLLFT1;ttBRGHTON.html
To see a GIF image file of the score of the song, or to download an ABC file of the score, visit this page of "The Session" - http://www.thesession.org/tunes/display/5418
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Now that a cold front has given central Florida back its nighttime sky, at least for a few evenings, this would be the perfect time to check out amazing Comet 17P/Holmes. In the early morning of October 24, Spanish amateur astronomer Juan Santana noticed that normally dim Comet 17P/Holmes had brightened considerably from observations made on previous nights. The sudden million-fold increase in brightness allowed the comet to become visible to the naked eye. The comet's coma, or outer cloud of gas and dust, is now physically much larger than the planet Jupiter.
It was just such an eruption of gas and dust that allowed the comet to be discovered in November of 1892 by English amateur astronomer Edwin Holmes. This is an excellent imaging target for off-the-shelf digital cameras and backyard telescopes.
The comet is still located just to the East (left) of the constellation Perseus. If you are in the Tampa Bay area, Perseus will rise in the North East and be completely above the horizon after 7PM EST. Comet 17P/Holmes should be visible roughly one-third of the way between Mirfak, the brightest star in Perseus, and the first magnitude wintertime star Capella, the brightest star in the constellation Auriga.
BACKGROUND: Comet 17P/Holmes was discovered by British amateur astronomer Edwin Holmes (1842-1919) on November 6, 1892 while conducting regular observations of the Andromeda Galaxy (M31). The orbital specifics for the comet are as follows: Aphelion distance, 5.2004 AU; Perihelion distance, 2.1655 AU; Semi-major axis, 3.618 AU ; Eccentricity, 0.4120; Orbital period, 7.0679 a (Julian years, lasting 362.25 days); Inclination, 19.1877°; Last perihelion, May 4, 2007; Next perihelion (predicted), March 27, 2014.
For more details and new information, check out these Web pages:
Space Weather Home Page:
http://spaceweather.com/
Space Weather Sky Chart:
http://spaceweather.com/images2007/24oct07/skymap_north_holmes.gif?PHPSESSID=ctmhv5tmpkfnk942ajcl3k17o7
Sky and Telescope Article:
http://www.skyandtelescope.com/observing/home/10862521.html
Phoenix Tilts Its Wings
On November 6, NASA's Phoenix Mars Lander mission team performed a spacecraft orientation adjustment to allow its solar panels to receive more energy from the sun.
During the first three months of the University of Arizona-led mission, which launched August 4, the spacecraft's solar panels were not pointed directly at the sun. If they had, the closer proximity to the sun would have overwhelmed the spacecraft's electrical systems.
With the spacecraft having covered 165 million miles of its 423 million mile journey to Mars, it receives less power as its distance from the sun increases.
The spacecraft also recently did a second trajectory correction maneuver that put it on course to be captured by the Martian gravitation field as it nears the planet. The spacecraft's original course was set from launch so that it would avoid hitting the planet if control problems arose. Additional trajectory corrections are scheduled for April and May to fine-tune the spacecraft's path to its landing site.
The lander is slated to arrive on Mars May 25. The Phoenix mission will look for evidence of water and the elements of life on Mars. It will analyze soil and ice samples scooped from the planet's northern arctic region.
The $420 million mission is led by University of Arizona, the first public institution to lead a mission to Mars. To learn more, visit the mission home page: http://phoenix.lpl.arizona.edu/
Five-Planet Star System Discovered
On November 06, NASA scientists announced the discovery of a record-setting fifth planet discovered orbiting a single star. The discovery suggests that multi-planet systems such as ours may not be unusual.
The star is the sunlike 55 Cancri, located 41 light-years away in the constellation Cancer. Researchers describe the new planet as a "mini-Saturn" of about 46 Earth masses. It is the fourth out from the star in a large gap between the third and fifth planets, placing it in the estimated habitable zone around the star where water might remain liquid.
The planet's size implies that it is a Jovian-like planet of hydrogen and helium gas, but the finding raises the possibility that earthlike moons might be orbiting the planet.
55 Cancri's system of five planets all seem to orbit along relatively circular paths, and the farthest planet out, a gaseous super-giant the size of four Jupiters, orbits at roughly the same distance from its star as the the distance of our Jupiter from the sun.
55 Cancri's innermost planet, weighing in at more than 10 earth masses—meaning it could have a rocky or icy core—lies closer to its star than Mercury does to our own. The new planet sits at 0.8 earth-sun distances (astronomical units) from the star, or roughly the distance between Venus and the sun. Before this discovery, researchers knew of only one other four-planet system, Mu Arae, and several three-planet systems.
55 Cancri system is one of many stars that for 18 years have been carefully and regularly measured by California's Lick Observatory and Hawaii's Keck Telescope. Researchers looked at the star's Doppler shift--the change in the wavelength, or color, of its light as it moved toward and away from Earth. A star tugged by an orbiting planet will wobble slightly, which can be detected as a regular shift in the star's color corresponding to the time the planet requires to complete an orbit. For example, 55 Cancri's outer planet has an orbital period of 14 years, and so was not discovered until 2004.
The research team's report has been accepted for future publication in The Astrophysical Journal. To learn more about the discovery and the observatories participating in the research, check these links:
University of California Observatories, Lick Observatory:
http://www.ucolick.org/
W. M. Keck Observatory:
http://www.keckobservatory.org/
Leonid Meteors Return
November 17 marks the peak of the annual Leonid meteor shower. Meteors from this shower may be visible from Nov. 15 through Nov. 20. Leonid meteors have an entry velocity of 71 km/second and glow with a bluish-green tint. This shower is caused by Periodic Comet 55P/Tempel-Tuttle, which returns to the inner solar system every 32.9 years. Meteor hourly rates are irregular and may reach 40 or greater in years surrounding the return of the comet. But since that last occurred in 1999, we can probably expect a rate of 10 to 15 per hour. The best chances to see Leonids are in the early morning hours during the days surrounding the peak (Nov. 16, 17, 18). The meteors will appear to originate from a point in the constellation of Leo (RA 10hrs 08min, Dec +22°).
The Leonids played a great role in our understanding of meteor showers. The great meteor storm of November 12-13, 1833 is regarded as the date of the birth of meteor astronomy. Following that meteor storm, Professors Olmsted and Twining of then Yale College pointed out that the meteors appeared to radiate from a point in the constellation Leo, the Lion. The fact that the meteors radiated from a single point indicated that they were all part of a swarm of meteoroids moving in the same orbital path. Later, Professor Hubert Anson Newton (1830-1896) an astronomer and mathematician who was also of Yale College, calculated that the orbit had a period of 33 years and used records to trace appearances of the shower as far back as AD 902. He also observed that the time of the Leonid shower moved along the calendar at the rate of about a month in a hundred years. Newton then successfully predicted the appearance of the 1866 Leonid storm. A few weeks after the 1866 storm astronomers found that the orbit of the meteoroid stream was identical with Temple's Comet, seen a year earlier. About this same time Italian astronomer Giovanni Schiaparelli (1835-1910) showed that the Perseid meteors came from a stream that moved in an orbit identical to the bright comet of 1862. These were the first observations to connect comets with the fall meteor showers.
There is historical evidence that Abraham Lincoln (1809-1865) also witnessed the great Leonid meteor storm of 1833 as a young man of 24. According to cross-referenced records and personal journals, Lincoln was apparently in New Salem, Illinois staying at the Rutledge Tavern, a log cabin then owned by Henry Onstot, a cooper by trade (bucket and barrel maker) and member of the Cumberland Presbyterian Church. Lincoln recounted the story in the presence of American writer Walt Whitman (1819-1892) who was a frequent guest of the Lincoln White House. Whitman later published the story in his book "Specimen Days & Collect," published in 1882. When asked by another White House guest whether the Union would survive the ongoing Civil War, Whitman noted that Lincoln, ever the story-teller, replied with this story. "When I was a young man in Illinois," said he, "I boarded for a time with a Deacon of the Presbyterian church. One night I was roused from my sleep by a rap at the door, & I heard the Deacon's voice exclaiming 'Arise, Abraham, the day of judgement has come!' I sprang from my bed & rushed to the window, and saw the stars falling in great showers! But looking back of them in the heavens I saw all the grand old constellations with which I was so well acquainted, fixed and true in their places. Gentlemen, the world did not come to an end then, nor will the Union now."
Thank Yous
Thanks to MARS member James Dagget who, following our report on quasars in early galaxies, shared his memories of working in the Quasar TV plant in Plantation, Florida the 1970s. James knows better than most about the inconsistent "quality" that went into those sets before the name went on.
Thanks to MARS member Craig MacDougal for sharing his backyard binocular observation of Comet 17P/Holmes during an all-too-brief break in the cloud cover last week. At that time the comet shone brighter than second magnitude and still continues to impress us now.
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MARS IS COMING, PART 2
As we prepare for the December 24 opposition, please enjoy this next installment on the Red Planet Mars.
Early Observations
Mars was a puzzle to ancient astronomers. They did not understand why it sometimes moved through the sky in the same direction as the sun and other celestial objects (direct, or prograde, motion), and sometimes moved in the opposite direction (retrograde motion). In 1609 the German mathematician and astronomer Johannes Kepler (1571-1630) used the excellent naked-eye observations of Danish astronomer Tycho Brahe (1546-1601) to deduce empirically the laws of motion for Mars and so pave the way for the modern gravitational theory of the solar system. Rather than having a circular orbit with uniform motion, as suggested by earlier Ptolemy-inspired theories, Kepler found that the orbit of Mars was an ellipse along which the planet moved with non-uniform but predictable motion--faster when closer to the sun, slower when farther away.
The earliest telescopic observations of Mars were made in 1610 by Italian astronomer Galileo Galilei (1564-1642) . This was also the first time that Mars was clearly seen not as a point of light, but as a disk. The Dutch scientist and mathematician Christiaan Huygens (1629-1695) is credited with the first accurate drawings of the planet's surface markings. In 1659 Huygens made a drawing that showed a major dark marking that is now known as Syrtis Major. About 1666, the Martian polar caps were first noted by the Italian-born French astronomer Gian Domenico Cassini (1625-1712).
Many key discoveries were made by visual observers. In 1659, Huygens discovered that Mars rotates and, in 1666, measured that rotation to be 24 hours 40 minutes--over today’s measurement by only 3 minutes. In the 1780s, German-born British astronomer William Herschel (1738-1822) first noted the very thin Martian atmosphere, and Herschel also measured the tilt of the planet's rotation axis and first discussed the Martian seasons. In 1877 the U.S. Naval Observatory's Asaph Hall (1829-1907) discovered that Mars has two natural satellites. Visual observers also documented many meteorological and seasonal changes that occur on Mars, such as various cloud types, the growing and shrinking of the polar caps, changes in the color and size of the dark areas, an annual "wave of darkening" in the markings that sweeps across the planet in time with the shrinking of the polar caps, and an occasional "blue haze" in the atmosphere. Most of these events were not explained until Mars was visited by spacecraft.
Visible Surface Features
Aside from the white polar caps, Earth-based telescopes show Mars generally to have a bright red-orange-colored surface that is covered by dark markings. Originally, the bright areas were called deserts, and most of the large dark areas were called maria (Latin, meaning "oceans" or "seas") because observers once thought the dark areas were covered by water.
The dark markings cover about one-third of the surface, mostly in a band around the planet between latitudes 10° and 40° South. They are irregularly distributed, and their overall pattern can change over many years. The northern hemisphere has only three major dark features. One is called Acidalia Planitia, another is called Syrtis Major, and the third is a dark collar around the northern pole. These were once thought to be shallow seas or areas of vegetation. We now know that Mars' dark areas form and change as the winds move surface material. Images from orbiting spacecraft reveal that the dark areas are actually collections of many dark streaks and splotches that are associated with craters, ridges, hills, and other geologic features that can block the local winds.
The bright areas, which cover about two-thirds of the surface, have subtle shadings, but these probably also are the result of the winds moving surface material. Beginning in 1877 with Italian astronomer Giovanni Schiaparelli (1835-1910) and into the early 20th century, maps of Mars showed many canals or channels—thin lines connecting the darker surface markings and thought by some at the time to be transportation for agricultural irrigation. However, these markings were not seen later in the images taken by flyby and orbiting spacecraft. The canals were apparently features that observers thought they saw while trying to push the resolution limits of their telescopes. Other features, such as the "wave of darkening" and the "blue haze" described by early telescopic observers, are now known to result from a combination of the viewing conditions and changes in the reflective properties of the surface.
For telescopic observers, the most dramatic regular changes on Mars occur at the poles. As fall begins in a particular hemisphere, clouds develop over that polar region, and the cap, made of frozen carbon dioxide, begins to grow. The smaller cap in the north can extend to 55° latitude, the larger cap in the south can extend to 50° latitude. In spring the caps recede. During northern summer the northern carbon dioxide cap disappears completely, leaving behind a small water-ice cap. And during the southern summer there is a small residual cap composed of carbon dioxide ice and water ice.
Early telescopic observers noted times when Martian surface features were temporarily hidden. They generally thought these were caused by white clouds or yellow clouds, and they interpreted the white clouds to be gas and the yellow clouds to be dust. Spacecraft images have since confirmed these interpretations were correct, and that hazes, clouds, and fogs regularly hide the surface.
Images from spacecraft in Mars orbit have found a variety of low-lying clouds and fogs, often in topographic depressions such as valleys or craters. They have also revealed high, thin clouds, particularly at the terminator--the dividing line between the daytime and nighttime portions of the planet's observable disk. Orographic clouds, which are produced when moist air is lifted over elevated terrain and cooled, form around prominent topographic features such as craters and volcanoes. Winter at the middle latitudes is characterized by westward-moving, spiral-shaped storm systems that are similar to those on Earth. Most of these clouds are composed of water ice--the white clouds that were seen by the early telescopic observers.
Dust storms are common on Mars. They can occur at any time but are most frequent in southern spring and summer, when Mars is passing closest to the sun and surface temperatures are at their highest. Most of the storms are regional in extent and last a few weeks. But every two or three years, the dust storms become global. At their peak, dust is carried so high in the atmosphere that only the summits of the tallest volcanoes--up to 21 km (13 miles) above the planet's mean radius--are visible. Although too small to be observed from Earth, the small sand tornados, called dust devils, have been seen by spacecraft in Mars orbit and by surface craft such as Mars Pathfinder and the Mars Exploration Rovers.
Next time: "The Martian Atmosphere"
Bibliography
Mars. (2007). In Encyclopædia Britannica. Retrieved October 26, 2007 , from Encyclopædia Britannica Online: http://www.britannica.com/eb/article-9110149
Mars (2007). In The Columbia Encyclopedia, Sixth Edition 2007. Copyright 2007 Columbia University Press. Retrieved October 26, 2007 from Encyclopedia.com
http://www.encyclopedia.com/doc/1E1-Mars-ast.html
Planets: Mars. In NASA Solar System Exploration, Last updated October 23, 2007. Retrieved October 26, 2007, from the NASA Solar System Exploration website, maintained by NASA's Jet Propulsion Laboratory:
http://solarsystem.jpl.nasa.gov/planets/profile.cfm?Object=Mars
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THE SKY THIS WEEK
Nov 11 - Dwarf Planet Ceres is at opposition (7.2 Magnitude)
Nov 11 – the star Antares is 0.4° north of the moon, occultation. An occultation occurs when one object passes in front of a smaller one, temporarily obscuring all or part of the background object from view.
Nov 12 – Jupiter is 5° north of the moon
Nov 12 - Dwarf Planet Ceres at its closest approach to Earth (1.832 AU)
Nov 14 – Asteroid Juno is in conjunction with the sun
Nov 15 - Mars is stationary. The body appears motionless in the sky due to the turning point between its direct and retrograde motion.
Nov 17, 5:33 P.M. EST - First Quarter Moon
Nov 17 - Neptune is 1.0° north of the moon, occultation. An occultation occurs when one object passes in front of a smaller one, temporarily obscuring all or part of the background object from view.
Nov 17 – the moon occults the planet Neptune
Nov 17 - Leonid Meteor Shower Peak
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THIS WEEK IN HISTORY
Nov 11, 1572 - Tycho Brahe's Discovery of a supernova, SN1572, 435th anniversary
Nov 11, 1875 - Vesto Slipher's birthday
Nov 11, 1966 - Gemini 12 launch (Jim Lovell and Buzz Aldrin)
Nov 12, 1891 - Seth Nicholson's birthday
Nov 12, 1924 - Audouin Dollfus' birthday
Nov 12, 1980 - Voyager 1, Saturn Flyby
Nov 13, 1831 - James Clerk Maxwell's birthday
Nov 14, 1969 - Apollo 12 Launch (Manned Moon Mission)
Nov 14, 1971 - Mariner 9, Mars Orbit Insertion
Nov 16, 2001 - Genesis, L1 Orbit Insertion
Nov 17, 1597 - Henry Gellibrand's 410th Birthday
Nov 17, 1966 – Leonid Meteor Storm
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MUSICAL DIVERSION
The song called "The Girl I Left Behind Me" has much folklore associated with it. Some say the song’s tune was popular as far back as the reign of Queen Elizabeth I, and that it was regularly played when regiments left town or when man-of-war ships set sail.
One source reports that the tune was known in America as early as 1650 and that it was a traditional fife tune, imported from England as "Brighten Camp." The tune became generally popular during the American Revolution. The tune was known in Ireland as "The Rambling Laborer" and "The Spailpin Fanach" and was first published in Dublin in 1791.
The tune is easy to play on the fife--a small flute. This song, along with “Yankee Doodle,” is often associated with the famous painting called “The Spirit of ’76.”
There are many settings for this tune. Below are two version of “The Girl I Left Behind Me.” The first comes from a collection called “Songs of the Seventh Calvary.” The origin of the other version is not certain. A third song based on this tune follows them.
The Girl I Left Behind Me
(from “Songs of the Seventh Calvary”)
The hours sad I left a maid
A lingering farewell taking
Whose sighs and tears my steps delayed
I thought her heart was breaking
In hurried words her name I blest
I breathed the vows that bind me
And to my heart in anguish pressed
The girl I left behind me
Then to the east we bore away
To win a name in story
And there where dawns the sun of day
There dawned our sun of glory
The place in my sight
When in the host assigned me
I shared the glory of that fight
Sweet girl I left behind me
Though many a name our banner bore
Of former deeds of daring
But they were of the day of yore
In which we had no sharing
But now our laurels freshly won
With the old one shall entwine me
Singing worthy of our size each son
Sweet girl I left behind me
The hope of final victory
Within my bosom burning
Is mingling with sweet thoughts of thee
And of my fond returning
But should I n'eer return again
Still with thy love i'll bind me
Dishonors breath shall never stain
The name I leave behind me
-----
The Girl I Left Behind Me
(an alternate version)
I'm lonesome since I crossed the hill,
And o'er the moorland sedgy
Such heavy thoughts my heart do fill,
Since parting with my Betsey
I seek for one as fair and gay,
But find none to remind me
How sweet the hours I passed away,
With the girl I left behind me.
O ne'er shall I foget the night,
the stars were bright above me
And gently lent their silv'ry light
when first she vowed to love me
But now I'm bound to Brighton camp
kind heaven then pray guide me
And send me safely back again,
to the girl I left behind me
Her golden hair in ringlets fair,
her eyes like diamonds shining
Her slender waist, her heavenly face,
that leaves my heart still pining
Ye gods above oh hear my prayer
to my beauteous fair to find me
And send me safely back again,
to the girl I left behind me
The bee shall honey taste no more,
the dove become a ranger
The falling waters cease to roar,
ere I shall seek to change her
The vows we made to heav'n above
shall ever cheer and bind me
In constancy to her I love,
the girl I left behind me.
-----
"Waxie's Dargle" is an old drinking song that is set to the same tune. Waxies were candlemakers, traditionally women, and "dargle" was a term for their annual working trip to Bray in Ireland. The River Dargle begins up in the Wicklow Mountains and finally empties into Irish Sea in Bray Harbor. Another source says the Dargle (a popular pub) was also a holiday haunt of the late eighteenth century Dublin candlemaker and grocer, Waxy O'Connor.
Here are some translations for the lyrics. “Auld one,” or old one, means wife. “Auld lad,” or old lad, means husband. In some versions the word “Uncle” is substituted with the phrase "Young Kill."
Waxie's Dargle
Says my auld one to your auld one
Will you come to the Waxie's dargle
Says your auld one to my auld one
Sure I haven't got a farthing
I've just been down to Monto town
To see Uncle McArdle
But he wouldn't lend me a half a crown
To go to the Waxie's dargle
Chorus:
What'll you have, will you have a pint
Yes, I'll have a pint with you, sir
And if one of us doesn't order soon
We'll be thrown out of the boozer
Says my auld one to your auld one
Will you come to the Galway races
Says your auld one to my auld one
With the price of my auld lad's braces
I went down to Capel Street
To the pawn shop money lenders
But they wouldn't give me a couple of bob
On my auld lad's red suspenders
(chorus)
Says my auld one to your auld one
We've got no beef nor mutton
But if we go down to Monto town
We might get a drink for nothin'
Here's a piece of good advice
I got from an auld fish-monger
When food is scarce and you see the hearse
You'll know you've died of hunger
(chorus)
-----
To review some the history, the text, or to listen to the melody, check out this pages from the "Songs of England" section of "Contemplations from the Marianas Trench - Music and Deep Thoughts"
- (The Girl I left Behind Me, Version 1) http://www.contemplator.com/england/girl.html
- (The Girl I left Behind Me, Version 2) http://www.contemplator.com/england/girl2.html
- (Waxie's Dargle) http://www.contemplator.com/england/waxie.html
To see a GIF image file of the score of the song, or to download an ABC file of the score, or other notations, visit this mirror site of Digital Tradition - http://sniff.numachi.com/pages/tiGIRLLFT1;ttBRGHTON.html
To see a GIF image file of the score of the song, or to download an ABC file of the score, visit this page of "The Session" - http://www.thesession.org/tunes/display/5418
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Friday, November 02, 2007
Dwarf Galaxies Also Have Dark Matter
U.S. astronomers have discovered that stars in dwarf spheroidal galaxies behave in a way that suggests they are dominated by dark matter.
University of Michigan astronomy Professor Mario Mateo and post-doctoral researcher Matthew Walker measured the velocity of 6,804 stars in seven dwarf Milky Way satellite galaxies: Carina, Draco, Fornax, Leo I, Leo II, Sculptor, and Sextans. They found that, contrary to Newton's law of gravity, the stars in those galaxies don't move slower the farther they are from their galaxy's core. Instead, they stayed the same. Astronomers were already aware that the stars in spiral galaxies behave in a similar way.
Their research shows that, if Newtonian laws still apply, then dwarf galaxies must be dominated by dark matter.
Dark matter is a substance astronomers haven't directly observed. But they deduce its existence because of its gravitational effects on visible matter.
The findings more than double the amount of data having to do with dwarf galaxies, allowing the galaxies to be studied in an unprecedented manner. The findings appeared in the September 20 issue of the Astrophysical Journal, and Walker will present a paper on the findings October 30 at Magellan Science Meeting in Cambridge, Massachusetts.
To learn more about the University of Michigan Observatories, go here:
http://www.astro.lsa.umich.edu/obs/
Exciting New Astronomy Journal
Astronomy enthusiasts, rejoice! It just became a lot easier for you to understand and explain the world of astronomy. On October 26 the International Astronomical Union (IAU) released the first issue of a new peer-reviewed journal. The publication will provide astronomy communicators with important tools and innovative resources to communicate more effectively the workings of the Universe to the public.
The publication is called the "Communicating Astronomy with the Public Journal," or "CAPjournal." The journal reflects the IAU's commitment to improve the global level of astronomy education and outreach.
The journal came about in this way. An IAU commission prepared a study assessing the feasibility of what became the "CAPjournal." The commission concluded that the present situation of public astronomy communication shows a clear need for a publication addressing the specific needs of the public astronomy communication community.
The main objectives of the new journal are:
- documenting and absorbing knowledge ("Teach and Train");
- providing a basis for discussions;
- compelling further progress;
- establishing priorities in a field;
- furthering careers (through documentation of the excellence of the individual);
- and helping to avoid the duplication of effort.
The journal will be published quarterly, and is divided in nine main sections dedicated to: "News", "Announcements", "Letters to the Editor", "Reviews", "Research & Applications", "Resources", "Innovations", "Best practices" and "Opinion". The "Research & Applications" section contains peer-reviewed science communication 'research' articles. "News" and "Announcements" present information and updates, such as conference reports from the astronomy outreach community. "Resources" and "Innovation" provide a repository of outreach ideas and cutting-edge astronomy communication methods respectively. "Best Practices" aims to be a guide, containing case studies, to the techniques that work best in communicating astronomy. "Opinion" provides space for subjective discussions of topics related to astronomy communication.
The quarterly journal will be published for free in print and online -- yes, I said free. It will act as a repository of ideas for astronomy communicators; for example in use with activities as part of the International Year of Astronomy 2009 which will be a global celebration of astronomy and its contributions to society and culture.
The first two issues are sponsored by the European Space Agency, the International Astronomical Union, Instituto de Astrofísica de Canarias (Spain) and ESO. I have seen no details as to how later issues will be sponsored, but let's hope they will continue to be free.
Free subscription forms and the online version of the journal can be found at http://www.capjournal.org
Three New Exoplanets
Three new planets have been discovered by a team from four UK universities. Powerful cameras in South Africa and the Canary islands found the planets, thought to be the size of Jupiter. The exoplanets (planets outside of our solar system) have been named WASP-3, WASP-4 and WASP-5, and are located in our galaxy.
The planets are so close to their stars that their 'year' (their orbit) lasts less than two days, among the shortest orbital periods yet discovered. Because they are so close to their stars, the surface temperatures of the planets will be more than 2,000C, so astronomers think it unlikely that life as we know it could survive there.
The new planets were discovered by the Wide Area Search for Planets (WASP) project. WASP comprises two robotic observatories designed to detect exoplanets using transiting techniques. The two observatories, located in La Palma and South Africa have been developed with funding by a consortium of four UK universities (Keele, St Andrews, Queen's University Belfast, and Leicester). Of the nearly 200 known exoplanets, less than a dozen are transiting. Using an all-sky survey such as WASP will identify many more candidate targets for more detailed investigation.
The WASP transiting technique is particularly powerful in that it enables the mass and size of the exoplanets to be studied, thereby allowing investigation of planet formation and development. Potentially, observations during primary and secondary eclipse could allow the derivation of spectral and spatial information about the detected planets.
The announcement of the discovery was made October 31. The WASP team are the only ones to find new planets in both the northern and southern hemispheres. To learn more about the WASP project, visit their Weblink: http://www.superwasp.org/wasp_planets.htm
Massive Black Hole Smashes Record
Do you remember the announcement on October 17 of M33 X-7, the stellar-mass black hole in M33? It has mass of 15.7 times that of the sun, which made it the most massive stellar-mass black hole known -- until now (My, how time flies).
Using two NASA satellites, astronomers have discovered the new most massive stellar-mass black hole to orbit a star. It has a mass 24 to 33 times that of our sun, more massive than scientists expected for a black hole that formed from a dying star.
The team which made the discovery was led by Andrea Prestwich of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts. Prestwich is also the lead author of the discovery paper in the November 1 Astrophysical Journal Letters. A team member and coauthor Roy Kilgard of Wesleyan University in Middletown, Connecticut.
"Stellar-mass" black holes form in the death throes of massive stars and they are, relatively speaking, much smaller than the supermassive black holes found in galactic cores. But the discovery of such a massive stellar-mass black hole was bit of a surprise. They had not expected a dying star to have that much leftover mass for the black hole. Astronomers are now rethinking what the new upper mass limit might be for a stellar-mass black hole.
The black hole is located in the nearby dwarf galaxy IC 10, which is 1.8 million light-years from Earth in the constellation Cassiopeia. The team could measure the mass of the black hole because it has an orbiting companion: a hot, highly evolved star (a Wolf-Rayet star, a type destined to explode as a supernova). The star is ejecting gas in the form of a solar wind. Some of this material spirals toward the black hole, heats up, and gives off powerful X-rays before crossing the black hole's event horizon -- the point of no return.
In November 2006, the team observed the dwarf galaxy with NASA's Chandra X-ray Observatory. The group discovered that the galaxy's brightest X-ray source, IC 10 X-1, exhibits sharp changes in X-ray brightness. That behavior suggested a star was periodically passing in front of a companion black hole and blocking the X-rays, creating an eclipse. In late November, NASA's Swift satellite confirmed the eclipses (which have a frequency of once every 34.4 hours) and Swift revealed more details about the star's orbit. The star in IC 10 X-1 appears to orbit in a plane that lies nearly edge-on to Earth's line of sight, The Swift observations, as well as observations from the Gemini Telescope in Hawaii, told the team how fast the two stars go around each other. Calculations showed that the companion black hole has a mass of at least 24 suns.
There are still some uncertainties in the black hole's mass estimate, but future optical observations will provide a final check. The team thinks that any refinements in the IC 10 X-1 measurement will likely increase the black hole's estimated mass rather than reduce it.
The black hole's large mass is surprising because massive stars generate powerful winds that blow off a large fraction of the star's mass before it explodes. Calculations suggest massive stars in our Milky Way galaxy leave behind black holes no heavier than about 15 to 20 suns.
The IC 10 X-1 black hole has gained mass since its birth by gobbling up gas from its companion star, but the rate is so slow that the black hole would have gained no more than 1 or 2 solar masses. The rest of the mass had to come from the original star. The team thinks the star probably started its life with 60 or more solar masses. Like its host galaxy, it was probably deficient in elements heavier than hydrogen and helium. In massive, luminous stars with a high fraction of heavy elements, the extra electrons of elements such as carbon and oxygen "feel" the outward pressure of light and are thus more susceptible to being swept away in stellar winds. But with its low fraction of heavy elements, the IC 10 X-1 progenitor shed comparatively little mass before it exploded, so it could leave behind a heavier black hole.
The team also noted that massive stars in our galaxy today are probably not producing very heavy stellar-mass black holes, but there could be, waiting to be discovered, many heavy stellar-mass black holes produced early in the Milky Way's history, before it had a chance to build up heavy elements.
To learn more about the discovery, and about the NASA' s Swift Gamma-Ray Burst Mission, go here: http://heasarc.gsfc.nasa.gov/docs/swift/swiftsc.html and to learn more about the Gemini Observatory, check out: http://www.gemini.edu
Robert T. McCall Artwork Donation
I mention this story because I think it is just so cool. On October 9, the amazing artist Robert T. McCall announced his donation to the University of Arizona Museum of Art (UAMA) of more than 200 original pieces. The collection is valued at nearly $3 million.
McCall has been painting for nearly seven-decade and the donated works include documentation of more than 35 years of the U.S. space program. McCall formally announced his gift at the opening of an exhibit of his works at the Paradise Valley Town Hall. The 18 pieces on display there are part of the collection going to the UA Museum of Art. The collection, which includes McCall's personal archives and notes, is a lead gift to establish the Archive of Visual Arts (AVA) at the UAMA.
In addition to being a visual historian for NASA, McCall has served as a conceptual artist for the entertainment industry. One of his most well known commercial pieces is the poster art for the classic motion picture 2001: A Space Odyssey.
McCall and his wife Louise live in Paradise Valley and McCall is a longtime supporter of the UA's efforts in space exploration, serving on the University's astronomy board.
To view wonderful examples of McCall's work, visit his online gallery:
http://www.mccallstudios.com/
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MARS IS COMING, PART 1
Mars is approaching opposition and will give us its best views until the next opposition in early 2010. Mars will be closest to Earth on December 18/19 and will finally reach opposition with Earth on December 24. We have some time before then, but with every day that passes Mars will appear larger and larger in our eyepieces. I therefore thought I would take this opportunity to share bits of information about the Red Planet as we approach this opposition. Here is the first installment.
Mars, An Introduction
Mars is the fourth planet in the solar system in order of distance from the sun and the seventh planet in size and mass. It is a noticeable and sometimes very bright, reddish object in the night sky -- some would say blood-red -- and it is sometimes called the Red Planet. The reddish color is caused by high iron content on the Martian soil. Mars has long been associated with warfare, death and suffering. Today we call the planet by the name of the Roman god of war. But 3,000 years ago, Babylonian astronomers/astrologers called the planet Nergal, the name of their god of death and pestilence. Mars has two moons, named Phobos ("Fear") and Deimos ("Terror"). These were the names of two of the sons of the Greek god Ares (the counterpart of Mars) and the Greek goddess Aphrodite (the counterpart of Venus). Mars is designated by the symbol of a circle and angled arrow, representing a warrior's spear and shield.
Mars orbits the sun at an average distance of 227,936,640 km (141,633,260 miles). That is 1.523662 times the average distance of Earth, or 1.523662 A.U. The Martian day (called a "sol") lasts 24.62 Earth hours, and the Martian year lasts 686.93 Earth days. Mars' equatorial diameter is 6,794 km (4,220 miles) -- just over have the diameter of Earth. Its density is only 0.714 times that of Earth, and its mass is only 0.17044 times that of Earth. In addition, Mars has little or no magnetic field. This fact, combined with its mass and density, suggest that Mars has very little metal in its core. As you might have already guessed, the surface gravity of Mars is much less than Earth. If you weighted 100 on Earth you would way only 38 pounds on Mars.
Mars has an axial tilt to its orbital plane of 25.19°, so Mars has seasons. The planet surface temperature ranges from -87 to -5°C (-125 to 23°F) and the average daytime surface temperature is 20°C (10°F). Mars has a very thin atmosphere compared to Earth, 0.7–0.9 kilopascal units, about 1/126 that of Earth. The Martian atmosphere includes carbon dioxide (95%), some nitrogen (2.5%) and argon (1.5%) and traces of carbon monoxide, water vapor, and other molecules and compounds. The atmosphere in the past appears to have been much denser and warmer with much more water. Some spacecraft images suggest that some liquid water flowed near the surface in relatively recent times. To date, no life has been detected.
Spacecraft images show a long and complex history of geological activity. The most noticeable feature is the contrast between the mostly smooth, lowland volcanic plains of the northern hemisphere and the heavily cratered uplands of the southern hemisphere. Martian geological features include a cratered surface, volcanoes, lava plains, flood channels, and giant canyons. Olympus Mons, the largest known volcano in the solar system, is hundreds of kilometers across and 27km (17mi) high. The polar ice caps vary in size with the season and appear to be composed of solid carbon dioxide with smaller caps of water ice underneath. Wind is an important element on Mars. It sculpts features such as dunes, occasionally causing global dust storms.
Next Time: “Early Observations and Visible Surface Features”
Bibliography
Mars. (2007). In Encyclopædia Britannica. Retrieved October 26, 2007 , from Encyclopædia Britannica Online: http://www.britannica.com/eb/article-9110149
Mars (2007). In The Columbia Encyclopedia, Sixth Edition 2007. Copyright 2007 Columbia University Press. Retrieved October 26, 2007 from Encyclopedia.com
http://www.encyclopedia.com/doc/1E1-Mars-ast.html
Mars (2005). In World Encyclopedia. Copyright 2005 World Encyclopedia 2005, originally published by Oxford University Press 2005. Retrieved October 26, 2007 from Encyclopedia.com
http://www.encyclopedia.com/doc/1O142-Mars.html
Planets: Mars. In NASA Solar System Exploration, Last updated October 23, 2007. Retrieved October 26, 2007, from the NASA Solar System Exploration website, maintained by NASA's Jet Propulsion Laboratory:
http://solarsystem.jpl.nasa.gov/planets/profile.cfm?Object=Mars
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THE SKY THIS WEEK
Nov 3/4 - Peak of the Southern Taurid Meteor Shower. This is one of two showers visible in the fall and winter that originate from the constellation Taurus. Both of these showers appear to be caused by Periodic Comet Encke. The other shower is called the Northern Taurid shower The Southern Taurid meteors are visible from September 15 through December 15 with the peak on November 3. The average meteor rate ranges from 5 to 15 per hour. The coordinates for the radiant of the Southern Taurid shower is RA 03hrs 44min, +14°.
Meteors are best viewed from a dark-sky location. Observers in for the duration of the evening, or at least for several hours, should bring along a few things: a sleeping bag or blankets for warmth, a recliner or lawn chair, a hot beverage to help cut the chill, and binoculars to view the smoke trails of just-past meteors.
Nov 4 - End Daylight Saving in United States. Set clocks back 1 hour
Nov 5 - Venus is 3° north of Moon
Nov 8 - Mercury is 7° north of Moon
Nov 8 - Mercury is at its greatest western elongation (19°)
Nov 9, 6:03 P.M. EST - New Moon
Nov 9 - Moon at apogee, the point in the Moon's orbit when it is farthest from Earth.
Nov 9 - Dwarf Planet Ceres at opposition, the point when a solar system body orbiting farther from the Sun than Earth appears opposite the Sun in the sky. Opposition is the best time to observe a body.
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THIS WEEK IN HISTORY
Nov 4, 1981 - Venera 14 Launch (USSR Venus Lander/Flyby)
Nov 5, 1906 - Fred Whipple's birthday
Nov 7, 1966 - Lunar Orbiter 2 launch
Nov 7, 1967 - Surveyor 6 launch (Moon Lander), 40th anniversary
Nov 7, 1996 - Mars Global Surveyor launch
Nov 8, 1656 - Edmund Halley's birthday
Nov 8, 1960 - Little Joe 5 launch, test of the launch escape system of Mercury production spacecraft #3. The flight was a failure and the spacecraft was destroyed.
Nov 8, 1982 - Wethersfield Meteorite Fall (Hit House), 25th anniversary
Nov 9, 1934 - Carl Sagan's birthday
Nov 9, 1967 - 1st Saturn V Launch (Apollo 4), 40th anniversary
Nov 10, 1970 - Luna 17 Launch (USSR Moon Rover)
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MUSICAL DIVERSION
"Tramp! Tramp! Tramp!" and "Jesus Loves the Little Children"
"Tramp! Tramp! Tramp!" was written in 1864 by George Frederick Root (1820-1895). Root, who was named after George Frideric Handel, was a music educator and composer, noted for his sacred and patriotic music. Among his other patriotic credits are "The Battle Cry of Freedom," "Just Before the Battle, Mother," "The Shining Shore," and "The First Gun Is Fired" which was written in April 1861 after the firing on Fort Sumter. "Tramp! Tramp! Tramp!" became one of the most popular songs of the American Civil War. The song opens in the cell of a military prison, but the chorus expresses hope for rescue and ultimate victory. At first, the song was sung only by the troupes in the Northern armies. Later, Confederate lyrics were written (by an author unknown) and the Confederate version became just as popular in the Southern armies.
Tramp! Tramp! Tramp!
(Original, Northern version)
In the prison cell I sit,
Thinking Mother dear of you,
And our bright and happy home so far away,
And the tears they fill my eyes
Spite of all that I can do
Though I try to cheer my comrades
and be gay.
Refrain:
Tramp! tramp! tramp!
The boys are marching
Cheer up comrades,
They will come.
And beneath the starry flag
We shall breathe the air again
Of the free land in our own beloved home.
In the battle front we stood
When their fiercest charge they made,
And they swept us off a hundred men or more;
But before we reached their lines
They were beaten back, dismayed,
And we heard the cry of vict'ry o'er and o'er.
(Refrain)
So within the prison cell
We are waiting for the day
That shall come to open wide the iron door;
And the hollow eye grows bright
And the poor heart almost gay
As we think of seing home and friends once more.
(Refrain)
----------
Tramp! Tramp! Tramp!
(Confederate version)
In my prison cell I sit,
thinking, Mother, dear, of you,
and my happy Southern home so far away;
and my eyes they fill with tears
'spite of all that I can do,
though I try to cheer my comrades and be gay.
Refrain:
Tramp! Tramp! Tramp!
The boys are marching;
cheer up, comrades, they will come.
And beneath the stars and bars
we shall breathe the air again
of freemen in our own beloved home..
(Refrain)
In the battle front we stood
when their fiercest charge they made,
and our soldiers by the thousands sank to die;
but before they reached our lines,
they were driven back dismayed,
and the "Rebel yell"went upward to the sky.
(Refrain)
Now our great commander Lee
crosses broad potomac's stream,
and his legions marching Northward take their way.
On pennsylvania's roads
will their trusty muskets gleam,
and her iron hills shall echo to the fray.
(Refrain)
In the cruel stockade-pen
dying slowly day by day,
for weary months we've waited all in vain;
but if God will speed the way
of our gallant boys in gray,
I shall see your face, dear Mother, yet again.
(Refrain)
When I close my eyes in sleep,
all the dear ones 'round me come,
at night my little sister to me calls;
and mocking visions bring
all the warm delights of home,
while we freeze and starve in Northern prison walls.
(Refrain)
So the weary days go by,
and we wonder as we sigh,
if with sight of home we'll never more be blessed.
Our hearts within us sink,
and we murmur, though we try
to leave it all with him who knowest best.
(Refrain)
----------
Some time after the war, the tune went in a different direction. One of Root's favorite lyricist, Clare Herbert Woolston (1856-1927), wrote a new hymn text that was set to Root's melody. It is said that Woolston was inspired by the Bible verse Matthew 1:14 where Jesus says, "Let the children come to me. Don't stop them! For the Kingdom of Heaven belongs to such as these." Not everyone recalls the verses of the hymn, but the refrain is often sung today as a hymn in itself.
Jesus Loves The Little Children
Jesus calls the children dear,
"Come to me and never fear,
For I love the little children of the world;
I will take you by the hand,
Lead you to the better land,
For I love the little children of the world."
Refrain:
Jesus loves the little children,
All the children of the world.
Red and yellow, black and white,
All are precious in His sight,
Jesus loves the little children of the world.
[Alternate refrain:
Jesus died for all the children,
All the children of the world.
Red and yellow, black and white,
All are precious in His sight,
Jesus died for all the children of the world.]
Jesus is the Shepherd true,
And He'll always stand by you,
For He loves the little children of the world;
He's a Savior great and strong,
And He'll shield you from the wrong,
For He loves the little children of the world.
(Refrain)
I am coming, Lord, to Thee,
And Your soldier I will be,
For You love the little children of the world;
And Your cross I'll always bear,
And for You I'll do and dare,
For You love the little children of the world.
(Refrain)
----------
To review the Northern version of "Tramp! Tramp! Tramp!", visit this page of the "Popular Songs in American History" section of section of "Contemplations from the Marianas Trench - Music and Deep Thoughts" - http://www.contemplator.com/america/tramptramp.html
To review the Confederate version of "Tramp! Tramp! Tramp!", visit this page of the "Popular Songs in American History" section of section of "Contemplations from the Marianas Trench - Music and Deep Thoughts" - http://www.contemplator.com/america/trampsouth.html
To see and hear more on the hymn, " Jesus Loves the Little Children" visit this page of "The Cyber Hymnal" - http://www.cyberhymnal.org/htm/j/e/jesloves.htm
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U.S. astronomers have discovered that stars in dwarf spheroidal galaxies behave in a way that suggests they are dominated by dark matter.
University of Michigan astronomy Professor Mario Mateo and post-doctoral researcher Matthew Walker measured the velocity of 6,804 stars in seven dwarf Milky Way satellite galaxies: Carina, Draco, Fornax, Leo I, Leo II, Sculptor, and Sextans. They found that, contrary to Newton's law of gravity, the stars in those galaxies don't move slower the farther they are from their galaxy's core. Instead, they stayed the same. Astronomers were already aware that the stars in spiral galaxies behave in a similar way.
Their research shows that, if Newtonian laws still apply, then dwarf galaxies must be dominated by dark matter.
Dark matter is a substance astronomers haven't directly observed. But they deduce its existence because of its gravitational effects on visible matter.
The findings more than double the amount of data having to do with dwarf galaxies, allowing the galaxies to be studied in an unprecedented manner. The findings appeared in the September 20 issue of the Astrophysical Journal, and Walker will present a paper on the findings October 30 at Magellan Science Meeting in Cambridge, Massachusetts.
To learn more about the University of Michigan Observatories, go here:
http://www.astro.lsa.umich.edu/obs/
Exciting New Astronomy Journal
Astronomy enthusiasts, rejoice! It just became a lot easier for you to understand and explain the world of astronomy. On October 26 the International Astronomical Union (IAU) released the first issue of a new peer-reviewed journal. The publication will provide astronomy communicators with important tools and innovative resources to communicate more effectively the workings of the Universe to the public.
The publication is called the "Communicating Astronomy with the Public Journal," or "CAPjournal." The journal reflects the IAU's commitment to improve the global level of astronomy education and outreach.
The journal came about in this way. An IAU commission prepared a study assessing the feasibility of what became the "CAPjournal." The commission concluded that the present situation of public astronomy communication shows a clear need for a publication addressing the specific needs of the public astronomy communication community.
The main objectives of the new journal are:
- documenting and absorbing knowledge ("Teach and Train");
- providing a basis for discussions;
- compelling further progress;
- establishing priorities in a field;
- furthering careers (through documentation of the excellence of the individual);
- and helping to avoid the duplication of effort.
The journal will be published quarterly, and is divided in nine main sections dedicated to: "News", "Announcements", "Letters to the Editor", "Reviews", "Research & Applications", "Resources", "Innovations", "Best practices" and "Opinion". The "Research & Applications" section contains peer-reviewed science communication 'research' articles. "News" and "Announcements" present information and updates, such as conference reports from the astronomy outreach community. "Resources" and "Innovation" provide a repository of outreach ideas and cutting-edge astronomy communication methods respectively. "Best Practices" aims to be a guide, containing case studies, to the techniques that work best in communicating astronomy. "Opinion" provides space for subjective discussions of topics related to astronomy communication.
The quarterly journal will be published for free in print and online -- yes, I said free. It will act as a repository of ideas for astronomy communicators; for example in use with activities as part of the International Year of Astronomy 2009 which will be a global celebration of astronomy and its contributions to society and culture.
The first two issues are sponsored by the European Space Agency, the International Astronomical Union, Instituto de Astrofísica de Canarias (Spain) and ESO. I have seen no details as to how later issues will be sponsored, but let's hope they will continue to be free.
Free subscription forms and the online version of the journal can be found at http://www.capjournal.org
Three New Exoplanets
Three new planets have been discovered by a team from four UK universities. Powerful cameras in South Africa and the Canary islands found the planets, thought to be the size of Jupiter. The exoplanets (planets outside of our solar system) have been named WASP-3, WASP-4 and WASP-5, and are located in our galaxy.
The planets are so close to their stars that their 'year' (their orbit) lasts less than two days, among the shortest orbital periods yet discovered. Because they are so close to their stars, the surface temperatures of the planets will be more than 2,000C, so astronomers think it unlikely that life as we know it could survive there.
The new planets were discovered by the Wide Area Search for Planets (WASP) project. WASP comprises two robotic observatories designed to detect exoplanets using transiting techniques. The two observatories, located in La Palma and South Africa have been developed with funding by a consortium of four UK universities (Keele, St Andrews, Queen's University Belfast, and Leicester). Of the nearly 200 known exoplanets, less than a dozen are transiting. Using an all-sky survey such as WASP will identify many more candidate targets for more detailed investigation.
The WASP transiting technique is particularly powerful in that it enables the mass and size of the exoplanets to be studied, thereby allowing investigation of planet formation and development. Potentially, observations during primary and secondary eclipse could allow the derivation of spectral and spatial information about the detected planets.
The announcement of the discovery was made October 31. The WASP team are the only ones to find new planets in both the northern and southern hemispheres. To learn more about the WASP project, visit their Weblink: http://www.superwasp.org/wasp_planets.htm
Massive Black Hole Smashes Record
Do you remember the announcement on October 17 of M33 X-7, the stellar-mass black hole in M33? It has mass of 15.7 times that of the sun, which made it the most massive stellar-mass black hole known -- until now (My, how time flies).
Using two NASA satellites, astronomers have discovered the new most massive stellar-mass black hole to orbit a star. It has a mass 24 to 33 times that of our sun, more massive than scientists expected for a black hole that formed from a dying star.
The team which made the discovery was led by Andrea Prestwich of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts. Prestwich is also the lead author of the discovery paper in the November 1 Astrophysical Journal Letters. A team member and coauthor Roy Kilgard of Wesleyan University in Middletown, Connecticut.
"Stellar-mass" black holes form in the death throes of massive stars and they are, relatively speaking, much smaller than the supermassive black holes found in galactic cores. But the discovery of such a massive stellar-mass black hole was bit of a surprise. They had not expected a dying star to have that much leftover mass for the black hole. Astronomers are now rethinking what the new upper mass limit might be for a stellar-mass black hole.
The black hole is located in the nearby dwarf galaxy IC 10, which is 1.8 million light-years from Earth in the constellation Cassiopeia. The team could measure the mass of the black hole because it has an orbiting companion: a hot, highly evolved star (a Wolf-Rayet star, a type destined to explode as a supernova). The star is ejecting gas in the form of a solar wind. Some of this material spirals toward the black hole, heats up, and gives off powerful X-rays before crossing the black hole's event horizon -- the point of no return.
In November 2006, the team observed the dwarf galaxy with NASA's Chandra X-ray Observatory. The group discovered that the galaxy's brightest X-ray source, IC 10 X-1, exhibits sharp changes in X-ray brightness. That behavior suggested a star was periodically passing in front of a companion black hole and blocking the X-rays, creating an eclipse. In late November, NASA's Swift satellite confirmed the eclipses (which have a frequency of once every 34.4 hours) and Swift revealed more details about the star's orbit. The star in IC 10 X-1 appears to orbit in a plane that lies nearly edge-on to Earth's line of sight, The Swift observations, as well as observations from the Gemini Telescope in Hawaii, told the team how fast the two stars go around each other. Calculations showed that the companion black hole has a mass of at least 24 suns.
There are still some uncertainties in the black hole's mass estimate, but future optical observations will provide a final check. The team thinks that any refinements in the IC 10 X-1 measurement will likely increase the black hole's estimated mass rather than reduce it.
The black hole's large mass is surprising because massive stars generate powerful winds that blow off a large fraction of the star's mass before it explodes. Calculations suggest massive stars in our Milky Way galaxy leave behind black holes no heavier than about 15 to 20 suns.
The IC 10 X-1 black hole has gained mass since its birth by gobbling up gas from its companion star, but the rate is so slow that the black hole would have gained no more than 1 or 2 solar masses. The rest of the mass had to come from the original star. The team thinks the star probably started its life with 60 or more solar masses. Like its host galaxy, it was probably deficient in elements heavier than hydrogen and helium. In massive, luminous stars with a high fraction of heavy elements, the extra electrons of elements such as carbon and oxygen "feel" the outward pressure of light and are thus more susceptible to being swept away in stellar winds. But with its low fraction of heavy elements, the IC 10 X-1 progenitor shed comparatively little mass before it exploded, so it could leave behind a heavier black hole.
The team also noted that massive stars in our galaxy today are probably not producing very heavy stellar-mass black holes, but there could be, waiting to be discovered, many heavy stellar-mass black holes produced early in the Milky Way's history, before it had a chance to build up heavy elements.
To learn more about the discovery, and about the NASA' s Swift Gamma-Ray Burst Mission, go here: http://heasarc.gsfc.nasa.gov/docs/swift/swiftsc.html and to learn more about the Gemini Observatory, check out: http://www.gemini.edu
Robert T. McCall Artwork Donation
I mention this story because I think it is just so cool. On October 9, the amazing artist Robert T. McCall announced his donation to the University of Arizona Museum of Art (UAMA) of more than 200 original pieces. The collection is valued at nearly $3 million.
McCall has been painting for nearly seven-decade and the donated works include documentation of more than 35 years of the U.S. space program. McCall formally announced his gift at the opening of an exhibit of his works at the Paradise Valley Town Hall. The 18 pieces on display there are part of the collection going to the UA Museum of Art. The collection, which includes McCall's personal archives and notes, is a lead gift to establish the Archive of Visual Arts (AVA) at the UAMA.
In addition to being a visual historian for NASA, McCall has served as a conceptual artist for the entertainment industry. One of his most well known commercial pieces is the poster art for the classic motion picture 2001: A Space Odyssey.
McCall and his wife Louise live in Paradise Valley and McCall is a longtime supporter of the UA's efforts in space exploration, serving on the University's astronomy board.
To view wonderful examples of McCall's work, visit his online gallery:
http://www.mccallstudios.com/
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MARS IS COMING, PART 1
Mars is approaching opposition and will give us its best views until the next opposition in early 2010. Mars will be closest to Earth on December 18/19 and will finally reach opposition with Earth on December 24. We have some time before then, but with every day that passes Mars will appear larger and larger in our eyepieces. I therefore thought I would take this opportunity to share bits of information about the Red Planet as we approach this opposition. Here is the first installment.
Mars, An Introduction
Mars is the fourth planet in the solar system in order of distance from the sun and the seventh planet in size and mass. It is a noticeable and sometimes very bright, reddish object in the night sky -- some would say blood-red -- and it is sometimes called the Red Planet. The reddish color is caused by high iron content on the Martian soil. Mars has long been associated with warfare, death and suffering. Today we call the planet by the name of the Roman god of war. But 3,000 years ago, Babylonian astronomers/astrologers called the planet Nergal, the name of their god of death and pestilence. Mars has two moons, named Phobos ("Fear") and Deimos ("Terror"). These were the names of two of the sons of the Greek god Ares (the counterpart of Mars) and the Greek goddess Aphrodite (the counterpart of Venus). Mars is designated by the symbol of a circle and angled arrow, representing a warrior's spear and shield.
Mars orbits the sun at an average distance of 227,936,640 km (141,633,260 miles). That is 1.523662 times the average distance of Earth, or 1.523662 A.U. The Martian day (called a "sol") lasts 24.62 Earth hours, and the Martian year lasts 686.93 Earth days. Mars' equatorial diameter is 6,794 km (4,220 miles) -- just over have the diameter of Earth. Its density is only 0.714 times that of Earth, and its mass is only 0.17044 times that of Earth. In addition, Mars has little or no magnetic field. This fact, combined with its mass and density, suggest that Mars has very little metal in its core. As you might have already guessed, the surface gravity of Mars is much less than Earth. If you weighted 100 on Earth you would way only 38 pounds on Mars.
Mars has an axial tilt to its orbital plane of 25.19°, so Mars has seasons. The planet surface temperature ranges from -87 to -5°C (-125 to 23°F) and the average daytime surface temperature is 20°C (10°F). Mars has a very thin atmosphere compared to Earth, 0.7–0.9 kilopascal units, about 1/126 that of Earth. The Martian atmosphere includes carbon dioxide (95%), some nitrogen (2.5%) and argon (1.5%) and traces of carbon monoxide, water vapor, and other molecules and compounds. The atmosphere in the past appears to have been much denser and warmer with much more water. Some spacecraft images suggest that some liquid water flowed near the surface in relatively recent times. To date, no life has been detected.
Spacecraft images show a long and complex history of geological activity. The most noticeable feature is the contrast between the mostly smooth, lowland volcanic plains of the northern hemisphere and the heavily cratered uplands of the southern hemisphere. Martian geological features include a cratered surface, volcanoes, lava plains, flood channels, and giant canyons. Olympus Mons, the largest known volcano in the solar system, is hundreds of kilometers across and 27km (17mi) high. The polar ice caps vary in size with the season and appear to be composed of solid carbon dioxide with smaller caps of water ice underneath. Wind is an important element on Mars. It sculpts features such as dunes, occasionally causing global dust storms.
Next Time: “Early Observations and Visible Surface Features”
Bibliography
Mars. (2007). In Encyclopædia Britannica. Retrieved October 26, 2007 , from Encyclopædia Britannica Online: http://www.britannica.com/eb/article-9110149
Mars (2007). In The Columbia Encyclopedia, Sixth Edition 2007. Copyright 2007 Columbia University Press. Retrieved October 26, 2007 from Encyclopedia.com
http://www.encyclopedia.com/doc/1E1-Mars-ast.html
Mars (2005). In World Encyclopedia. Copyright 2005 World Encyclopedia 2005, originally published by Oxford University Press 2005. Retrieved October 26, 2007 from Encyclopedia.com
http://www.encyclopedia.com/doc/1O142-Mars.html
Planets: Mars. In NASA Solar System Exploration, Last updated October 23, 2007. Retrieved October 26, 2007, from the NASA Solar System Exploration website, maintained by NASA's Jet Propulsion Laboratory:
http://solarsystem.jpl.nasa.gov/planets/profile.cfm?Object=Mars
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THE SKY THIS WEEK
Nov 3/4 - Peak of the Southern Taurid Meteor Shower. This is one of two showers visible in the fall and winter that originate from the constellation Taurus. Both of these showers appear to be caused by Periodic Comet Encke. The other shower is called the Northern Taurid shower The Southern Taurid meteors are visible from September 15 through December 15 with the peak on November 3. The average meteor rate ranges from 5 to 15 per hour. The coordinates for the radiant of the Southern Taurid shower is RA 03hrs 44min, +14°.
Meteors are best viewed from a dark-sky location. Observers in for the duration of the evening, or at least for several hours, should bring along a few things: a sleeping bag or blankets for warmth, a recliner or lawn chair, a hot beverage to help cut the chill, and binoculars to view the smoke trails of just-past meteors.
Nov 4 - End Daylight Saving in United States. Set clocks back 1 hour
Nov 5 - Venus is 3° north of Moon
Nov 8 - Mercury is 7° north of Moon
Nov 8 - Mercury is at its greatest western elongation (19°)
Nov 9, 6:03 P.M. EST - New Moon
Nov 9 - Moon at apogee, the point in the Moon's orbit when it is farthest from Earth.
Nov 9 - Dwarf Planet Ceres at opposition, the point when a solar system body orbiting farther from the Sun than Earth appears opposite the Sun in the sky. Opposition is the best time to observe a body.
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THIS WEEK IN HISTORY
Nov 4, 1981 - Venera 14 Launch (USSR Venus Lander/Flyby)
Nov 5, 1906 - Fred Whipple's birthday
Nov 7, 1966 - Lunar Orbiter 2 launch
Nov 7, 1967 - Surveyor 6 launch (Moon Lander), 40th anniversary
Nov 7, 1996 - Mars Global Surveyor launch
Nov 8, 1656 - Edmund Halley's birthday
Nov 8, 1960 - Little Joe 5 launch, test of the launch escape system of Mercury production spacecraft #3. The flight was a failure and the spacecraft was destroyed.
Nov 8, 1982 - Wethersfield Meteorite Fall (Hit House), 25th anniversary
Nov 9, 1934 - Carl Sagan's birthday
Nov 9, 1967 - 1st Saturn V Launch (Apollo 4), 40th anniversary
Nov 10, 1970 - Luna 17 Launch (USSR Moon Rover)
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MUSICAL DIVERSION
"Tramp! Tramp! Tramp!" and "Jesus Loves the Little Children"
"Tramp! Tramp! Tramp!" was written in 1864 by George Frederick Root (1820-1895). Root, who was named after George Frideric Handel, was a music educator and composer, noted for his sacred and patriotic music. Among his other patriotic credits are "The Battle Cry of Freedom," "Just Before the Battle, Mother," "The Shining Shore," and "The First Gun Is Fired" which was written in April 1861 after the firing on Fort Sumter. "Tramp! Tramp! Tramp!" became one of the most popular songs of the American Civil War. The song opens in the cell of a military prison, but the chorus expresses hope for rescue and ultimate victory. At first, the song was sung only by the troupes in the Northern armies. Later, Confederate lyrics were written (by an author unknown) and the Confederate version became just as popular in the Southern armies.
Tramp! Tramp! Tramp!
(Original, Northern version)
In the prison cell I sit,
Thinking Mother dear of you,
And our bright and happy home so far away,
And the tears they fill my eyes
Spite of all that I can do
Though I try to cheer my comrades
and be gay.
Refrain:
Tramp! tramp! tramp!
The boys are marching
Cheer up comrades,
They will come.
And beneath the starry flag
We shall breathe the air again
Of the free land in our own beloved home.
In the battle front we stood
When their fiercest charge they made,
And they swept us off a hundred men or more;
But before we reached their lines
They were beaten back, dismayed,
And we heard the cry of vict'ry o'er and o'er.
(Refrain)
So within the prison cell
We are waiting for the day
That shall come to open wide the iron door;
And the hollow eye grows bright
And the poor heart almost gay
As we think of seing home and friends once more.
(Refrain)
----------
Tramp! Tramp! Tramp!
(Confederate version)
In my prison cell I sit,
thinking, Mother, dear, of you,
and my happy Southern home so far away;
and my eyes they fill with tears
'spite of all that I can do,
though I try to cheer my comrades and be gay.
Refrain:
Tramp! Tramp! Tramp!
The boys are marching;
cheer up, comrades, they will come.
And beneath the stars and bars
we shall breathe the air again
of freemen in our own beloved home..
(Refrain)
In the battle front we stood
when their fiercest charge they made,
and our soldiers by the thousands sank to die;
but before they reached our lines,
they were driven back dismayed,
and the "Rebel yell"went upward to the sky.
(Refrain)
Now our great commander Lee
crosses broad potomac's stream,
and his legions marching Northward take their way.
On pennsylvania's roads
will their trusty muskets gleam,
and her iron hills shall echo to the fray.
(Refrain)
In the cruel stockade-pen
dying slowly day by day,
for weary months we've waited all in vain;
but if God will speed the way
of our gallant boys in gray,
I shall see your face, dear Mother, yet again.
(Refrain)
When I close my eyes in sleep,
all the dear ones 'round me come,
at night my little sister to me calls;
and mocking visions bring
all the warm delights of home,
while we freeze and starve in Northern prison walls.
(Refrain)
So the weary days go by,
and we wonder as we sigh,
if with sight of home we'll never more be blessed.
Our hearts within us sink,
and we murmur, though we try
to leave it all with him who knowest best.
(Refrain)
----------
Some time after the war, the tune went in a different direction. One of Root's favorite lyricist, Clare Herbert Woolston (1856-1927), wrote a new hymn text that was set to Root's melody. It is said that Woolston was inspired by the Bible verse Matthew 1:14 where Jesus says, "Let the children come to me. Don't stop them! For the Kingdom of Heaven belongs to such as these." Not everyone recalls the verses of the hymn, but the refrain is often sung today as a hymn in itself.
Jesus Loves The Little Children
Jesus calls the children dear,
"Come to me and never fear,
For I love the little children of the world;
I will take you by the hand,
Lead you to the better land,
For I love the little children of the world."
Refrain:
Jesus loves the little children,
All the children of the world.
Red and yellow, black and white,
All are precious in His sight,
Jesus loves the little children of the world.
[Alternate refrain:
Jesus died for all the children,
All the children of the world.
Red and yellow, black and white,
All are precious in His sight,
Jesus died for all the children of the world.]
Jesus is the Shepherd true,
And He'll always stand by you,
For He loves the little children of the world;
He's a Savior great and strong,
And He'll shield you from the wrong,
For He loves the little children of the world.
(Refrain)
I am coming, Lord, to Thee,
And Your soldier I will be,
For You love the little children of the world;
And Your cross I'll always bear,
And for You I'll do and dare,
For You love the little children of the world.
(Refrain)
----------
To review the Northern version of "Tramp! Tramp! Tramp!", visit this page of the "Popular Songs in American History" section of section of "Contemplations from the Marianas Trench - Music and Deep Thoughts" - http://www.contemplator.com/america/tramptramp.html
To review the Confederate version of "Tramp! Tramp! Tramp!", visit this page of the "Popular Songs in American History" section of section of "Contemplations from the Marianas Trench - Music and Deep Thoughts" - http://www.contemplator.com/america/trampsouth.html
To see and hear more on the hymn, " Jesus Loves the Little Children" visit this page of "The Cyber Hymnal" - http://www.cyberhymnal.org/htm/j/e/jesloves.htm
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