Sunday, December 30, 2007

ASTRONOMY NEWS AND EVENTS

Galactic Assault by a Black Hole

A powerful jet from a supermassive black hole is blasting a nearby galaxy, according to new data from NASA observatories. This never-before witnessed galactic violence may have a profound effect on planets in the jet's path and trigger a burst of star birth in its destructive wake.

These events are playing out in a faraway binary galaxy system known as 3C321. Two galaxies are in orbit around one another. A supermassive black hole at the core of the system's larger galaxy is spewing a jet in the direction of its smaller companion.

Jets from super massive black holes produce large amounts of radiation, especially high-energy X-rays and gamma-rays, which can be lethal in large quantities. The combined effects of this radiation and particles traveling at almost the speed of light could severely damage the atmospheres of planets lying in the path of the jet. For example, protective layers of ozone in the upper atmosphere of planets could be destroyed.

The effect of the jet on the companion galaxy is likely to be substantial, because the galaxies in 3C321 are extremely close at a distance of only about 20,000 light years apart. They lie approximately the same distance as Earth is from the center of the Milky Way galaxy.

The jet and galactic assault were discovered through the combined efforts of both space and ground-based telescopes. NASA's Chandra X-ray Observatory, Hubble Space Telescope, and Spitzer Space Telescope were part of the effort. Two sophisticated radio telescopes--the Very Large Array (VLA) in Socorro, New Mexico, and the Multi-Element Radio Linked Interferometer Network (MERLIN) in the United Kingdom--were also needed for the finding.

To learn more, visit these links:

NASA's Chandra X-ray Observatory:
http://chandra.harvard.edu/

Space Telescope Science Institute:
http://www.stsci.edu/resources/

NASA's Spitzer Space Telescope:
http://www.spitzer.caltech.edu/

NRAO Very Large Array (VLA) in Socorro, New Mexico:
http://www.vla.nrao.edu/

The Multi-Element Radio Linked Interferometer Network (MERLIN) in the United Kingdom:
http://www.merlin.ac.uk/


Scientists Find Another Source of Cosmic Dust

Scientists in California have uncovered the best evidence yet that cosmic dust in the early universe mostly came from the explosions of giant stars.

The Spitzer Space Telescope recently detected large amounts of space dust, 10,000 Earth masses worth, in the supernova remnant Cassiopeia A located 11,000 light-years away.
The discovery comes two months after Spitzer found freshly made dust in the wind bursting out of super-massive black holes.

Astronomers believe both supernovae and quasars are responsible for the dust that helped seed early stars. Dust is essential in the cooling process to make stars, which are predominantly gas.

Researchers at NASA's Spitzer Science Center at the California Institute of Technology analyzed infrared light from the supernova and constructed maps of the dust to determine the quantity and composition.

Results will be published in the January 20 issue of the Astrophysical Journal.

To learn more, check out the home page of the Spitzer Space Telescope: http://www.spitzer.caltech.edu


International Year of Astronomy 2009 (IYA2009)

On Thursday morning, December 20, the United Nations proclaimed 2009 to be the International Year of Astronomy, to mark the 400th anniversary of Italian astronomer Galileo Galilei's first observations using a telescope.

The UN 62nd General Assembly made the proclamation in Paris, after the resolution was submitted by Italy, Galileo's home country.

The International Astronomical Union and UNESCO will jointly run the initiative with 99 nations participating.

The focus of the UN program will be on astronomy for the masses. "The IYA2009 is, first and foremost, an activity for the citizens of planet Earth," the UN said in a statement. "It aims to convey the excitement of personal discovery, the pleasure of sharing fundamental knowledge about the universe and our place in it, and the merits of the scientific method."

Each year the UN proclaims a number of resolutions to connect certain calendar years with global issues and activities. In four separate declarations, the UN has proclaimed 2008 as the international year of sanitation, languages, planet Earth and the potato.

To learn more, check out the home page of the International Year of Astronomy 2009:
http://www.astronomy2009.org/


Jets Are a Real Drag

Astronomers have found the best evidence yet of matter spiraling outward from a young, still-forming star in fountain-like jets. Because of the spiral motion, the jets help the star to grow by drawing angular momentum from the surrounding accretion disk. Theorists knew that a star had to shed angular momentum as it formed, but this is the first evidence to support the theory.

Angular momentum is the tendency for a spinning object to continue spinning. It applies to star formation because a star forms at the center of a rotating disk of hydrogen gas. A star grows by gathering material from the disk. However, gas cannot fall inward toward the star until that gas sheds its excess angular momentum.

As hydrogen nears the star, a fraction of the gas is ejected outward perpendicular to the disk in opposite directions, like water from a fire hose, in a bipolar jet. If the gas spirals around the axis of the jet, then it will carry angular momentum with it away from the star.

Using the Submillimeter Array (SMA), an international team of astronomers observed an object called Herbig-Haro 211 (HH 211), located about 1,000 light-years away in the constellation Perseus. HH 211 is a bipolar jet traveling through interstellar space at supersonic speeds. The central protostar is about 20,000 years old with a mass only six percent the mass of our Sun. It eventually will grow into a star like the Sun.

The astronomers found clear evidence for rotation in the bipolar jet. Gas within the jet swirls around at speeds of more than 3,000 miles per hour, while also blasting away from the star at a velocity greater than 200,000 miles per hour.

In the future, the team plans to take a closer, more detailed look at HH 211. They also hope to observe additional protostar-jet systems.

A paper on this work was published in the December 1 issue of the Astrophysical Journal.

The paper was authored by Chin-Fei Lee (Academia Sinica Institute of Astronomy and Astrophysics, or ASIAA), Paul Ho (ASIAA and CfA), Aina Palau (Laboratorio de Astrofisica Espacial y Fisica Fundamental), Naomi Hirano (ASIAA), Tyler Bourke (CfA), Hsien Shang (ASIAA), and Qizhou Zhang (CfA).

The Submillimeter Array is an 8-element interferometer located atop Mauna Kea in Hawaii. It is a collaboration between the Smithsonian Astrophysical Observatory and the Institute of Astronomy and Astrophysics of the Academia Sinica of Taiwan.

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.

To learn more, visit these home pages
The Harvard-Smithsonian Center for Astrophysics:
http://www.cfa.harvard.edu/

The Submillimeter Array (SMA):
http://sma1.sma.hawaii.edu/


Exoplanet Reflected Light Detected

The ability to explore remote worlds in space has been enhanced through a polarization technique that allows the first ever detection of light reflected by extrasolar planets (exoplanets). The study has been accepted for publication in Astrophysical Journal Letters.

An international team of astronomers, led by Professor Svetlana Berdyugina of ETH Zurich's Institute of Astronomy, has for the first time ever been able to detect and monitor the visible light that is scattered in the atmosphere of an exoplanet. Employing techniques similar to how Polaroid sunglasses filter away reflected sunlight to reduce glare, the team of scientists were able to extract polarized light to enhance the faint reflected starlight 'glare' from an exoplanet. As a result, the scientists could infer the size of its swollen atmosphere. They also directly traced the orbit of the planet, a feat of visualization not possible using indirect methods.

The transiting exoplanet under study circles the dwarf star HD189733 in the constellation Vulpecula and lies more than 60 light years from the earth. Known as HD189733b, this exoplanet was discovered two years ago via Doppler spectroscopy. HD189733b is so close to its parent star that its atmosphere expands from the heat. Until now, astronomers have never seen light reflected from an exoplanet, although they have deduced from other observations that HD189733b probably resembles a 'hot Jupiter' - a planet orbiting extremely closely to its parent star. Unlike Jupiter, however, HD189733b orbits its star in a couple of days rather than the 12 years it takes Jupiter to make one orbit of the sun.

The international team, consisting of Svetlana Berdyugina, Dominique Fluri (ETH Zurich), Andrei Berdyugin and Vilppu Piirola (Tuorla Observatory, Finland), used the 60cm KVA telescope by remote control. The telescope, which belongs to the Royal Swedish Academy of Science, is located at La Palma, Spain and was modernized by scientists in Finland. The researchers obtained polarimetric measurements of the star and its planet. They discovered that polarization peaks near the moments when half of the planet is illuminated by the star as seen from the earth. Such events occur twice during the orbit, similar to half-moon phases.

The polarization indicates that the scattering atmosphere is considerably larger (>30%) than the opaque body of the planet seen during transits and most probably consists of particles smaller than half a micron, for example atoms, molecules, tiny dust grains or perhaps water vapor, which was recently suggested to be present in the atmosphere. Such particles effectively scatter blue light - in exactly the same scattering process that creates the blue sky of the earth's atmosphere. The scientists were also able for the first time to recover the orientation of the planet's orbit and trace its motion in the sky.

To learn more visit the home page of the Institute of Astronomy ETH Zurich:
http://www.astro.phys.ethz.ch/


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MARS IS COMING, PART 9 (MARS IS HERE)

As we bask in the light of Mars, please enjoy this, this last of our 9-part series on the Red Planet.


Spacecraft Exploration, Mapping Mars, and The Question of Life

Spacecraft Exploration

Since humans began sending rockets into space, Mars has been a focus of planetary exploration for three main reasons: first, it is the most Earth-like of the planets; second, other than Earth, it is the planet most likely to have developed indigenous life; and third, it will probably be the first extraterrestrial planet to be visited by humans. Between 1960 and 1980 the exploration of Mars was a major objective of both the U.S. and Soviet space programs. U.S. spacecraft successfully flew by Mars (Mariners 4, 6, and 7), orbited the planet (Mariner 9 and Vikings 1 and 2), and placed landers on its surface (Vikings 1 and 2). Three Soviet probes (Mars 2, 3, and 5) also investigated Mars, two of them reaching its surface. Mars 3 was the first spacecraft to soft-land an instrumented capsule on the planet, on December 2, 1971; landing during a planetwide dust storm, the device returned data for about 20 seconds.

Mariner 9, the first spacecraft to orbit another planet, entered orbit November 1971 and operated until October 1972. It returned a wide variety of spectroscopic, radio-propagation, and photographic data. Some 7,330 pictures covering 80 percent of the surface showing a history of widespread volcanism, ancient erosion by water, and reshaping of extensive areas of the surface by internal forces.

The central theme of the Viking missions was the search for extraterrestrial life. No definite evidence of biological activity was found, but the various instruments on the two orbiters and two landers returned detailed information about Martian geology, meteorology, and the physics and chemistry of the upper atmosphere. Vikings 1 and 2 were placed into orbit during June and August 1976, respectively. Lander modules descended to the surface from the orbiters after suitable sites were found. Viking 1 landed in the region of Chryse Planitia (Plain of Gold, 22° N, 48° W) on July 20, 1976, and Viking 2 landed 6,500 km (4,000 miles) away in Utopia Planitia (Plain of Utopia, 48° N, 226° W) on September 3, 1976.

In 1988 Soviet scientists launched a pair of spacecraft, Phobos 1 and 2, to orbit Mars and make slow flyby observations of its two satellites. Phobos 1 failed during the yearlong flight, but Phobos 2 reached Mars in early 1989 and returned several days of observations of both the planet and Phobos before malfunctioning.

Amid failures of several U.S. spacecraft missions to Mars in the 1990s, Mars Pathfinder successfully set down in Ares Vallis (Greek for Mars Valley), the end of one outflow channel emptying into Chryse Planitia (19° N, 33° W) on July 4, 1997, and deployed a robotic wheeled rover called Sojourner on the surface. This was followed by Mars Global Surveyor, which reached Mars in September 1997 and systematically mapped various properties of the planet from orbit for several years beginning in March 1999. These included Mars's gravity and magnetic fields, surface topography, and surface mineralogy. The spacecraft also carried cameras for making both wide-angle and detailed images of the surface at resolutions down to 1.5 meters (5 feet). Mars Odyssey safely entered Mars orbit in October 2001 and started mapping other properties, including the chemical composition of the surface, the distribution of near-surface ice, and the physical properties of near-surface materials.

A wave of spacecraft converged on Mars in late 2003 and early 2004 with mixed outcomes. Nozomi, launched by Japan in 1998 on a leisurely trajectory, was the first reach the vicinity of the planet, but malfunctions prevented it from being put into Mars orbit. In mid-2003 the European Space Agency's Mars Express was launched on a half-year journey to the Red Planet. Carrying instruments to study the atmosphere, surface, and subsurface, it entered Mars orbit on December 25; however, its lander, named Beagle 2, which was to examine the rocks and soil for signs of past or present life, failed to establish radio contact after presumably descending to the Martian surface the same day. Within weeks of its arrival, the Mars Express orbiter detected vast fields of water ice as well as carbon dioxide ice at the southern pole and confirmed that the southern summer remnant cap, like the northern one, contains permanently frozen water.

Also launched in mid-2003 was the U.S. Mars Exploration Rover Mission, which comprised twin robotic landers, Spirit and Opportunity. Spirit touched down in Gusev Crater (15° S, 175° E) on January 3, 2004. Three weeks later, on January 24, Opportunity landed in Meridiani Planum (2° S, 6° W), on the opposite side of planet. The six-wheeled rovers, each equipped with cameras and a suite of instruments that included a microscopic imager and a rock-grinding tool, analyzed the rocks, soil, and dust around their landing sites, which had been chosen because they appeared to have been affected by water in Mars's past. Both rovers found evidence of past water; perhaps the most dramatic was the discovery by Opportunity of rocks that appeared to have been laid down at the shoreline of an ancient body of salty water.

Mapping Mars

The first known map of Mars was produced in 1830 by Wilhelm Wolff Beer (1797-1850) and Johann Heinrich von Mädler (1794-1874) of Germany. The Italian astronomer Giovanni Virginio Schiaparelli (1835-1910) prepared the first modern astronomical map of Mars in 1877, which contained the basis of the system of nomenclature still in use today. The names on his map are in Latin and are formulated predominantly in terms of the ancient geography of the Mediterranean area. This map also showed, for the first time, indications of an interconnecting system of straight lines on the bright areas that he described as canali (Italian: “channels”). Schiaparelli is usually credited with their first description, but his fellow countryman Pietro Angelo Secchi (1818-1878) developed the idea of canali about a decade earlier. In 1894 the American astronomer Percival Lowell (1855-1916) established an observatory in Flagstaff, Arizona, specifically to observe Mars, and he produced ever more elaborate maps of the Martian canals until his death.

Observations made by Mariner 9 and subsequent Mars-orbiting spacecraft have led to many maps of topography, geology, temperature, mineral distributions, and a variety of other data. After Mariner 9, the prime meridian on Mars, the equivalent of the Greenwich meridian on Earth, was defined as passing through a small crater named Airy-0 within the larger crater Airy. Longitude was measured in degrees that increase to the west of this meridian completely around the planet. Later some scientists expressed a preference for a coordinate system having longitude that increases to the east of the prime meridian. Consequently, maps of Mars were published with either or both of these systems.

The Question of Life

The possible presence of life on Mars has been an essential element of general discussions of the planet since Schiaparelli first included canali on his maps. Lowell was particularly responsible for popularizing the notion that these markings were the result of biological activity, intelligent or otherwise. Nevertheless, as discussed above in the section Surface features, it has been clear since the 1960s that such features do not exist.

The biological experiments aboard the two Viking landers addressed three issues: first, the nature of organic material, if any, on the Martian surface, second, the possible presence of objects on the surface whose appearance or motion would suggest living or fossilized organisms, and third, the possible presence in Martian soil of agents that, under prescribed conditions, could indicate metabolic processes. The results related to the first issue were definite and unambiguous—a direct, extremely sensitive chemical analysis of samples at both lander sites showed no trace of complex organic materials. Addressing the second issue, the cameras on the landers found no evidence of biological agents or activity.

Three separate instruments addressed the last issue. One, the pyrolytic release experiment, was designed to look for signs of photosynthesis or chemosynthesis—that is, signs of biological activity supported by solar or chemical energy, respectively—in samples of Martian soil. This experiment produced some positive indications, but the experimenters thought that they could be best explained by non-biological processes. A second experiment, called the gas exchange experiment, measured gases released from a soil sample as it was exposed to a humid atmosphere or treated with a solution of organic nutrients. This experiment also produced a positive result in that the soil samples liberated substantial quantities of oxygen in response to the nutrient. This reaction, however, also occurred even after samples had been baked on-site at 145 °C (293 °F) for three hours, leading experimenters to conclude that the source of oxygen was non-biological. Finally, the labeled release experiment looked for the release of radioactive gas when a soil sample was exposed to a solution of radioactive organic nutrient. A positive result was again obtained, and in this case a baked control sample remained inert, as would be expected if the reaction was caused by a biological agent. Nevertheless, given the results of the other Viking experiments, most investigators think that the results of the labeled release experiment also can be explained non-biologically.

The Martian surface is almost certainly devoid of life at the present time. It is exposed to ultraviolet radiation from the Sun without any reduction in intensity by the atmosphere. Also, organic compounds in the soil are destroyed, probably by a combination of oxidation and photochemical processes. Moreover, average temperatures are so cold and the water content of the atmosphere so low that liquid water, universally accepted as essential for life, is unlikely to be readily available, although it may be episodically and locally available in view of evidence for seemingly recent water-worn gullies (see the section Southern cratered highlands, above). These considerations have encouraged scientists to shift their search for life on Mars to the search for past life. As was indicated above, different lines of evidence suggest that conditions on early Mars were much more hospitable to life than subsequently. If life did gain a foothold, it now may survive only in protected niches well below the hostile surface. The current strategy, therefore, is to focus on evidence of past life and then look for present life below the surface or where liquid water might be episodically available.

This strategy was underscored by the findings from the Martian meteorite ALH84001, which was collected from an Antarctic ice field in 1984. It is the oldest known rock from Mars, having formed about 4.5 billion years ago when the planet itself was accreting. It contains organic materials, evidence of mineral deposition from liquid water, and a number of structures similar to primitive terrestrial fossils. Although most scientists conclude that these findings do not provide good evidence for past life, they have stimulated closer examination of the Martian meteorites and have emphasized the need for obtaining samples from Mars, particularly of ancient rocks that were being formed or were already present when conditions on Mars were more Earth-like.


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

Dec 31, 2:51 A.M. EST (07:51 UTC) - Last quarter moon

Jan 1 - The dwarf planet Ceres is stationary. The body appears motionless in the sky due to the turning point between its direct and retrograde motion.

Jan 2 - Earth is at perihelion, the point in Earth's orbit when it is closest to the Sun (0.983 AU from the sun).

Jan 3 - The moon is at apogee, the point in the Moon's orbit when it is farthest from Earth.

Jan 3 - Peak of the Quadrantid meteor shower. Meteors from the Quadrantid shower may be visible from January 1 through 6 with the peak on January 3/4. The meteor hourly rates may range from 40 to possibly 110 at the shower's peak. The meteors will appear to originate from a point in the sky near the constellation of Boötes the Herdsman (RA 15hrs 28min, Dec +50°) high in the eastern sky. This is not a prime time shower. Ambitious observers will either have to get up very early or stay up very late. And you will only have a few hours to observe. The radiant point of the shower will begin rising about 1:00 a.m. but it will not reach its zenith before sunrise. The Quadrantid shower has no known parent comet. It was first noticed about 1835. Most meteor showers are named after the constellation which contains the radiant. The Quadrantids are the exception to this rule. These meteors come from an area of the now-rejected constellation Quadrans Muralis (the Mural Quantrant), which is now the northern part of the constellation Boötes. A mural quadrant was an early instrument used for measuring declination. It is a large graduated circle with a sighting arm and telescope. The word "mural" indicated that the instrument was
attached to a wall.

Jan 5 - The planet Venus is 7° north of the moon

Jan 5 - The star Antares is 0.5° 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.


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THIS WEEK IN HISTORY

Dec 30, 1985 - Stephen Synnott's discovery of Uranus moon Puck

Dec 31, 1905 - Discovery of Asteroid 583 Klotilde by Austrian astronomer Johann Palisa (1848 - 1925)

Jan ??, 2001 - Discovery of NWA 1669 Meteorite (Mars Meteorite)

Jan ??, 2001 - Discovery of NWA 1950 Meteorite (Mars Meteorite)

Jan ??, 2002 - Discovery of NWA 1110 Meteorite (Mars Meteorite)

Jan 1, 1801 - Discovery of the first asteroid (now dwarf planet) Ceres by Italian astronomer Guiseppe Piazzi (1746-1826)

Jan 1, 2005 - Appearance of the really cool JPL/Caltech float in the 2005 Tounament of Roses Parade

Jan 2, 1900 - Birthday of U.S. Astronomer Leslie Copus Peltier (1900 -1980)

Jan 2, 1959 - Launch of Soviet probe Luna 1 (1st Moon Flyby)

Jan 2, 1920 - Birthday of Isaac Asimov (ca. 1920-1992), writer of novels, short stories and textbooks, historian, biochemist, and humorist

Jan 3, 1886 - Birthday of Soviet/Russian astronomer Grigory Neujmin (January 3, 1886 [O.S. December 22, 1885] - December 17, 1946)

Jan 3, 1986 - Stephen Synnott's discovery of Uranus moons Juliet & Portia

Jan 3, 2004 - Landing of the Spirit Rover on Mars

Jan 4, 1643 - Birthday of Isaac Newton (January 4, 1643 [OS: December 25, 1642] - March 31, 1727 (aged 84) [OS: 20 March1727]), theologian, physicist, mathematician, astronomer, natural philosopher, alchemist

Jan 5, 1905 - discovery of Jupiter moon Elara by Argentine astromomer Charles Dillon Perrine (1867-1951)

Jan 5, 1969 - Launch of Soviet probe Venera 5 (Venus Lander)

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MUSICAL DIVERSION

The Scots Musical Museum is a six-volume publication that appeared between 1787 and 1803. Produced in Edinburgh by James Johnson with Stephen Clarke as musical editor, it is considered by many to be the finest collection of Scottish Songs.

The principal contributor, submitting over 300 of the total 600 published songs, without monetary compensation, was Robert Burns (1759 – 1796), a poet, lyricist, farmer, and exciseman (customs agent). He was also known as Rabbie Burns, but his writing earned him other names including the Ploughman Poet and the Bard of Ayrshire, where he spent most of his life. Later, Scotland simply called him The Bard. Burns is widely regarded as the national poet of Scotland and Scotland's favorite son.

In 1788 Burns set down the words to a particular song and sent it to Johnson soon after. Burns wrote that he "collected" the song from an old man who sang it. Johnson was hesitant to publish the "authentic" song because it contained bits of other old folk songs and poems, including one poem written by Robert Ayton (1570-1638) that Johnson had already published in an earlier volume. In addition, Johson probably knew it was not uncommon for a song collector to compose some or all of their "discovered" songs. In spite of all this, Johnson finally published the song in the fifth volume early in 1797. Sadly, Burns had died about six months earlier, but his letters suggest that Burns had seen proofs of the new volume before his death. The song in question was a tribute to remembered friendships and shared times, entitled "Auld Lang Syne."

The song became popular shortly after it was published, and that popularity spread to other English speaking countries as Scots and other Britons emigrated around the world. The song was often sung as a closing to momentous occasions, including but not limited to dances, comencement excercises and annual associational meetings or conferences. In keeping with this tradition of farewell and rembrance, many also sang it at the stroke of midnight on New Year's Day. In Scotland the celebration is called Hogmanay (pronounced "hog-muh-NAY"), meaning the last day of the year.

While "Auld Lang Syne" is still used for various occasions around the world, many in the United States know it only as that song we sing at midnight on New Year's Day. However, that does not lessen the significance of the words and the sentiment they offer.

The pentatonic melody we sing today is not the one that Burns intended. That tune appeared earlier with the Robert Ayton poem. Still, the final melody is a traditional Scots folk tune just the same, first appearing in print in 1700, but possibly older by fifty years or more. It is also possible that it began as a dance tune with a much faster tempo.

"Auld Lang Syne" (pronounced "ald lang sign") is sometimes described as "the song that nobody knows." Even in Scotland, it is rarely sung correctly. Most people sing only the first verse and the chorus, with the last line of the verse changed to "and days of auld lang syne." The Scots words "auld lang syne" literally mean "old long since." In today's English we would probably say "long ago" or "times gone by."

Below are listed three versions of the text. The first is the original submitted by Burns. The second is an English guide to pronouncing the Scots text. The last is an English translation of the Scots text.

-----

Auld Lang Syne
(Scots Text)

Should auld acquaintance be forgot,
And never brought to mind?
Should auld acquaintance be forgot,
And auld lang syne!

Chorus:

For auld lang syne, my dear,
For auld lang syne.
We'll tak a cup o' kindness yet,
For auld lang syne.

And surely ye'll be your pint stowp!
And surely I'll be mine!
And we'll tak a cup o'kindness yet,
For auld lang syne.

(chorus)

We twa hae run about the braes,
And pou'd the gowans fine;
But we've wander'd mony a weary fit,
Sin' auld lang syne.

(chorus)

We twa hae paidl'd in the burn,
Frae morning sun till dine;
But seas between us braid hae roar'd
Sin' auld lang syne.

(chorus)

And there's a hand, my trusty fere!
And gie's a hand o' thine!
And we'll tak a right gude-willie waught,
For auld lang syne.

(chorus)

-----

Auld Lang Syne
(English Pronunciation of Scots Text)

Shid ald akwentans bee firgot,
an nivir brocht ti mynd ?
Shid ald akwentans bee firgot,
an ald lang syn ?

Chorus:

Fir ald lang syn, ma dir,
fir ald lang syn,
Wil tak a cup o kyndnes yet,
fir ald lang syn.

An sheerly yil bee yur pynt-staup!
an sheerly al bee myn!
An wil tak a recht guid-wullae wocht,
fir ald lang syn.

(chorus)

We twa hay rin aboot the braes,
an pood the gowans fyn;
Bit weev wandert monae a weery fet,
sin ald lang syn.

(chorus)

We twa hay pedilt in the burn,
fray mornin sun til dyn;
But seas a'tween us bred hay roard
sin ald lang syn.

(chorus)

An thers a han, my trustee feer!
an gees a han o thyn!
An will tak a cup o kyndnes yet,
fir ald lang syn.

(chorus)

-----

Auld Lang Syne
(English Translation)

Should old acquaintance be forgot,
and never brought to mind?
Should old acquaintance be forgot,
and auld lang syne?

Chorus:

For auld lang syne, my dear,
for auld lang syne,
we'll take a cup o’ kindness yet,
for auld lang syne.

And surely you’ll buy your pint cup!
And surely I’ll buy mine!
And we’ll take a right good-will draught,
for auld lang syne.

(chorus)

We two have run about the slopes,
and picked the daisies fine ;
But we’ve wandered many a weary foot,
since auld lang syne.

(chorus)

We two have paddled in the stream,
from morning sun till dine (dinner time) ;
But seas between us broad have roared
since auld lang syne.

(chorus)

And there’s a hand my trusty friend!
And give us a hand o’ thine!
And we'll take a cup o’ kindness yet,
for auld lang syne.

(chorus)

-----


“Auld Lang Syne.” Wikipedia, The Free Encyclopedia. Last updated December 29, 2007 18:33 UTC. Retrieved from The Wikimedia Foundation, Inc. December 30, 2007:
http://en.wikipedia.org/wiki/Auld_Lang_Syne

“Auld Lang Syne.” The Burns Encyclopedia. Retrieved December 26, 2007 from Robert Burns Country:
http://www.robertburns.org/encyclopedia/AuldLangSyne.5.shtml

Burns, Robert. Auld Lang Syne. Retrieved December 27, 2007 from Robert Burns Country: http://www.robertburns.org/works/236.shtml

“Scots Musical Museum, The.” Wikipedia, The Free Encyclopedia. Last updated August 25, 2007 01:25 UTC. Retrieved from The Wikimedia Foundation, Inc. December 27, 2007:
http://en.wikipedia.org/wiki/Scots_Musical_Museum

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Sunday, December 23, 2007

Asteroid Could Hit Mars in January

A recently discovered asteroid which passed close to the Earth in November is now headed toward a very close pass of Mars in late January, and there is a small chance that it could hit. There is only a 1-in-75 chance of a collision, but scientists are excited about the possibility. If it happens, the impact would occur on January 30, 2008 at around 10:55 UT (5:55 a.m. EST).

In the likely event that the asteroid misses Mars, it could come back to the vicinity of Earth years or decades later, but routine hazard monitoring shows that there is no threat of an impact with the Earth.

Designated asteroid 2007 WD5, it was discovered on November 20, 2007 by the NASA-funded Catalina Sky Survey using a 1.5-meter telescope on Mt. Lemmon, near Tucson. The object had already passed within 7.5 million km (5 million miles) of Earth on November 1, before it was discovered. Based on its magnitude (brightness), they estimate the asteroid to be about 50 meters (160 feet) across. It has already reached the halfway point between Earth and Mars. When it closes in on Mars, it will approach from the day side, and will be very difficult to observe from any of the spacecraft on or around Mars. The current best estimate predicts the asteroid will miss Mars by 50,000 km, but the miss distance is highly uncertain because the asteroid's path is not known with sufficient accuracy. As of the December 21 announcement, the uncertainty region during the Mars encounter is over a million kilometers (700,000 miles) along a very slender ellipsoid only 1200 km (700 miles) wide, but the ellipsoid does intersect Mars. The zone of potential impact on the surface of Mars is approximately 800 km wide, and sweeps across the Martian equator from southwest to northeast, crossing the equator at roughly 30 degrees W longitude. The Mars Exploration Rover "Opportunity" is close to the southern edge of this possible impact zone but clearly outside it.

The asteroid is becoming increasingly harder to observe, since it is receding from the Earth and the waxing Moon is approaching the same part of the sky. But it should become observable again early in January. These new measurements will lead to a significant improvement in the orbit accuracy, and astronomers will then be able to refine the probability that the asteroid might collide with Mars.

If the asteroid does hit Mars, it would strike with a velocity of about 13.5 km/s (8.4 miles per second), and would produce an explosion equivalent to about 3 Megatons of TNT. Scientists can only speculate as to the effects of such an impact, but it would be reasonable to expect a crater nearly a kilometer across and a significant amount of dust lifted into the atmosphere.

An impact would not be unprecedented: 21 fragments of Comet Shoemaker-Levy 9 impacted Jupiter in July, 1994. Those impacts were predicted with near certainty almost a year before the impact. But, with a 1-in-75 chance, this asteroid's possible impact with Mars is far from certain.

To learn more, visit the home page of the NASA/JPL Near-Earth Object Program: http://neo.jpl.nasa.gov


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MARS IS COMING, PART 8 (MARS IS HERE)

Here we are. Opposition has arrived, December 24. As we bask in the glow of Mars, please enjoy this installment.

The Interior, Martian Meteorites and Martian Moons

The Interior

We know little about the Martian interior. Planetary scientists have yet to conduct a successful seismic experiment via spacecraft that would provide direct information on internal structure and so must rely on indirect inferences. The moment of inertia of Mars indicates that it has a central core with a radius of 1,300–2,000 km (800–1,200 miles). Isotopic data from meteorites determined to have come from Mars (see the section Meteorites from Mars, below) demonstrate unequivocally that the planet differentiated—separated into a metal-rich core and rocky mantle—at the end of the planetary accretion period 4.5 billion years ago. The planet has no detectable magnetic field that would indicate convection (heat-induced flow) in the core today. Large regions of magnetized rock have been detected in the oldest terrains, however, which suggests that very early Mars did have a magnetic field but that it disappeared as the planet cooled and the core solidified. Martian meteorites also suggest that the core may be more sulfur-rich than Earth's core and the mantle more iron-rich.

Scientists think that Mar is probably volcanically active today, although at a very low level. Some Martian meteorites, which are all volcanic rocks, show ages as young as a few hundred million years, and some volcanic surfaces on the planet are so sparsely cratered that they must be only tens of millions of years old. So Mars was volcanically active in the geologically recent past, which implies that its mantle is warm and undergoing melting locally.

Mars's gravitational field is very different from Earth's. On Earth, excesses and deficits of mass in the surface crust, corresponding to the presence of large mountains and ocean deeps, respectively, tend to be offset by compensating masses at depth (isostatic compensation). Thus, the pull of gravity on Earth is the same on high mountains as it is over the ocean. This is also true for Mars's oldest terrains, such as the Hellas basin, the southern highlands, and the northern plains. The younger terrains, such as the Tharsis and Elysium domes, however, are only partly compensated. Associated with both of these regions are gravity highs—that is, places where the measured gravity is significantly higher than elsewhere because of the large mass of the domes. (Similar areas, called mascons, have been detected and mapped on Earth's moon.)

Because the gravity over the southern highlands is roughly the same as that over the low-lying northern plains, the southern highlands must be underlain by a thicker crust of material that is less dense than the mantle below it. Estimates of the thickness of the Martian crust range from only 3 km (2 miles) under the Isidis impact basin, which is just north of the equator and east of Syrtis Major, to more than 90 km (60 miles) at the south end of the Tharsis rise.

Martian Meteorites

By 2004 scientists had identified about 30 meteorites that came from Mars. Suspicions about their origin were first raised when meteorites that appeared to be volcanic rocks were found to have ages of about 1.3 billion years instead of the 4.5 billion years of all other meteorites. These rocks had to have come from a body that was geologically active in the comparatively recent past, and Mars was the most likely candidate. The rocks also have similar ratios of oxygen isotopes, which are distinctively different from those of Earth rocks, lunar rocks, and other meteorites. A Martian origin was finally proved when it was found that several of them contained trapped gases having a composition identical to that of the Martian atmosphere as measured by the Viking landers. The rocks are thought to have been ejected from the Martian surface by large impacts. They then went into solar orbit for several million years before falling on Earth. Claims in the mid-1990s of finding evidence for past microscopic life in one of the meteorites, called ALH84001, have been viewed skeptically by the general science community.

Martian Moons

Little was learned about the two moons of Mars, Phobos and Deimos, from their discovery in 1877 until orbiting spacecraft observed them a century later. Viking 1 flew to within 100 km (60 miles) of Phobos and Viking 2 to within 30 km (20 miles) of Deimos.

Phobos orbits Mars once every 7 hours 39 minutes. It moves in a very close orbit at a mean distance of about 6,000 km (3,700 miles) from the surface—less than twice the planet's radius. It is so near that, without internal strength, it would be torn apart by gravitational (tidal) forces. These forces also slow the motion of Phobos and may ultimately cause the satellite to collide with Mars, possibly in less than 100 million years. The opposite fate is expected for Deimos. It moves in a more distant orbit, and tidal forces are causing it to recede from the planet. Phobos and Deimos are not visible from all locations on the planet because of their small size, their closeness to Mars, and their near-equatorial orbits.

Both moons are irregular chunks of rock, roughly ellipsoidal in shape. Phobos is the larger of the two. Phobos's rugged surface is completely covered with impact craters. The largest, the crater Stickney, is about half as wide as the satellite itself. Its surface also has a widespread system of linear fractures, or grooves, many of which are geometrically related to Stickney. In contrast, the surface of Deimos appears smooth, as its many craters are almost completely buried by fine debris, and it shows no fracture system. The difference in appearance between the two moons is thought to be related to the fate of the debris created by impacts. In the case of the inner, more massive Phobos, the ejected material either fell back to the surface or, if it left the satellite with enough velocity to go into space, subsequently fell on Mars. For the more distant, smaller Deimos, debris thrown off the satellite remained in orbit until it was recaptured, sifting down to blanket its surface.

The albedo, or reflectivity, of the surfaces of both moons is very low, similar to that of the most primitive types of meteorites. One theory of the origin of the moons is that they are asteroids that were captured when Mars was forming.

Next Time, Our Final Installment: "Spacecraft Exploration, Mapping Mars, and The Question of Life"

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.comhttp://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

Dec 23, 8:16 P.M. EST (Dec 24, 1:16 UTC) - Full Moon

Dec 23 - The planet Jupiter is in conjunction with the sun

Dec 23 - The planet Mars is 0.9° south 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.

Dec 24 - The planet Mars is at opposition. Opposition occurs when a planet farther from the sun than Earth appears opposite the sun in the sky. It is the best time to observe a planet.

Dec 25 - The moon occults Asteroid 15 Eunomia

Dec 27 - The star Regulus is 0.6° 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.

Dec 28 - The planet Saturn is 3° north of the moon


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THIS WEEK IN HISTORY

Dec 23, 1672 - Giovanni Cassini's Discovery of Saturn Moon Rhea

Dec 24, 1761 - Birthday of Jean-Louis Pons

Dec 24, 1905 - Joel Metcalf's Discovery of Asteroid 581 Tauntonia

Dec 24, 1965 - Barwell Meteorite Fall (Hit Car, Buildings)

Dec 24, 1979 - 1st Ariane 1 Launch

Dec 26, 1974 - Launch of Salyut 4 Launch (Soviet Space Station)

Dec 27, 1571 - Birthday of Johannes Kepler

Dec 27, 1904 - Max Wolf's Discovery of Asteroid 553 Kundry

Dec 27, 1984 - Discovery of ALH 84001 (Mars Meteorite)

Dec 28, 1882 - Birthday of Arthur Eddington

Dec 28, 1929 - Birthday of Maarten Schmidt

Dec 29, 1977 - Discovery of ALHA 77005 Meteorite (Mars Meteorite), 30th Anniversary


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MUSICAL DIVERSION

In 1816 a young Austrian priest, Father Josef Mohr (1792 - 1848) wrote in German a beautiful six-stanza poem on the birth of the Christ child. At that time Mohr was assigned to a pilgrimage church in the Alpine town of Mariapfarr, not far from the home of his grandfather. While we do not know what inspired Mohr to write his poem, we do know he took the poem with him when he was transferred to the village of Oberndorf the following year (1817).

Early on December 24, 1818 Mohr traveled quickly from Oberndorf to nearby Arnsdorf, to the home of musician and school teacher Franz Xaver Gruber (1787 - 1863), who lived in the apartment over the town schoolhouse. In addition to his teaching in Arnsdorf, Gruber was the organist and choir director at St. Nikolaus Church where Mohr served as assistant pastor. On this day Mohr showed Gruber his poem. He may have also given Gruber a bit of melody, but we are not certain. Mohr asked Gruber to finish the song and create an arrangement for duet and chorus with guitar accompaniment. The new song had to be ready for performance at Midnight Mass that night. We are not certain why the song had to be ready for that evening, but we have some possible reasons. Some have suggested that the organ was not working, either because of mice-eaten organ bellows or because of rust and mildew caused by periodic flooding of the nearby Salzach River. Others think that Mohr, who dearly loved guitar music, just wanted a new carol for Christmas. Whatever the reason, the song had to come together quickly.

Mohr returned to Oberndorf and Gruber followed several hours later with the finished arrangement. Mohr would sing melody and Gruber would sing a bass harmony. There was not enough time for the choir to learn and rehearse the entire song, so Gruber had the choir echo the duet by repeating the last two stanzas of each verse in four-part harmony. That night, at the Midnight Mass in St. Ni­ko­laus Church, Mohr and Gruber stood in front of the main alter and sang while Mohr played his guitar and the choir echoed. And so the carol "Stille Nacht! Heilige Nacht" (Silent Night, Holy Night) was heard for the first time.

Stille Nacht, Heilige Nacht!

Stille Nacht, heilige Nacht!
Alles schläft, einsam wacht
Nur das traute hochheilige Paar,
Holder Knabe mit lockigem Haar,
Schlaf in himmlischer Ruh,
Schlaf in himmlischer Ruh.

Stille Nacht, heilige Nacht!
Gottes Sohn, o wie lacht
Lieb’ aus deinem holdseligen Mund,
Da uns schlägt die rettende Stund’,
Christ, in deiner Geburt,
Christ, in deiner Geburt!

Stille Nacht, heilige Nacht!
Die der Welt Heil gebracht,
Aus des Himmels goldenen Höhn,
Uns der Gnaden Fülle läßt sehn,
Jesum in Menschengestalt,
Jesum in Menschengestalt!

Stille Nacht, heilige Nacht!
Wo sich heut alle Macht
Väterlicher Liebe ergoß,
Und als Bruder huldvoll umschloß
Jesus die Völker der Welt,
Jesus die Völker der Welt!

Stille Nacht, heilige Nacht!
Lange schon uns bedacht,
Als der Herr vom Grimme befreit
In der Väter urgrauer Zeit
Aller Welt Schonung verhieß,
Aller Welt Schonung verhieß!

Stille Nacht, heilige Nacht!
Hirten erst kund gemacht;
Durch der Engel Halleluja
Tönt es laut von fern und nah’;
Christ der Retter ist da,
Christ der Retter ist da!

-----

Below is the literal translation of the text from German to English by Bettina Klien.


Silent Night! Holy Night!
Silent Night! Holy Night!
All is calm, all is bright
Round yon godly tender pair.
Holy infant with curly hair,
Sleep in heavenly peace,
Sleep in heavenly peace.

Silent Night! Holy Night!
Son of God, love's pure light
Radiant beams from thy holy face,
With the dawn of redeeming grace,
Jesus, Lord at thy birth
Jesus, Lord at thy birth.

Silent Night! Holy Night!
Brought the world gracious light,
Down from heaven's golden height
Comes to us the glorious sight:
Jesus, as one of mankind,
Jesus, as one of mankind.

Silent Night! Holy Night!
By his love, by his might
God our Father us has graced,
As a brother gently embraced
Jesus, all nations on earth,
Jesus, all nations on earth.

Silent Night! Holy Night!
Long ago, minding our plight
God the world from misery freed,
In the dark age of our fathers decreed:
All the world redeemed,
All the world redeemed.

Silent Night! Holy Night!
Shepherds first saw the sight
Of angels singing alleluia
Calling clearly near and far:
Christ, the Saviour is born,
Christ, the Saviour is born.

-----

Over the next few years Karl Mauracher, a master organ builder and repairman from the Ziller Valley, made several trips to Oberndorf to work on the St. Nikolaus organ. During one of these visits he either found or was given a copy of the carol and he took it home with him. The carol then began its journey around the world as a "Tyrolean Folk Song."

Two traveling families of folk singers from the Ziller Valley, named Strasser and Rainer, added the song into their performing repertoire. We know from the local newspaper that the Strassers sang the song in a concert in Leipzig in December 1832. It was during this time that several of the melody’s notes were changed, and it evolved into the melody we commonly hear. We also know from a historical plaque that the Rainer Family sang the carol before an audience which included Austrian Emperor Franz I and Russian Tsar Alexander I. In 1839, the Rainers performed "Stille Nacht" for the first time in America, at the Alexander Hamilton Monument outside Trinity Church in New York City.

Although Gruber made attempts during his life to claim authorship of the carol melody, it was thought at various times that the melody was composed by Haydn, Mozart or Beethoven. The controversy was finally put to rest when an arrangement of the song written in Mohr's own hand was found and authenticated. The authorities could also plainly see in the upper right hand corner of the first page that Mohr had written, "Melodie von Fr. Xav. Gruber."

Gruber produced a number of orchestral arrangements of the song during his life. The original guitar arrangement is missing, but five other Gruber manuscripts of the carol exist. The discovered manuscript by Joseph Mohr (ca. 1820) is for guitar accompaniment and is probably the closest to the arrangement and melody sung at Midnight Mass in 1818.
The people of Austria consider the song a national treasure. They traditionally perform it only on Christmas Eve.

Below is an English translation of the hymn found in many western hymnals. Stanzas 1 and 3 were translated from German in 1863 by John F. Young (1820 – 1885). The translator of stanzas 2 and 4 is unknown.


Silent Night, Holy Night!

Silent night, holy night,
All is calm, all is bright
Round yon virgin mother and Child.
Holy Infant, so tender and mild,
Sleep in heavenly peace,
Sleep in heavenly peace.

Silent night, holy night,
Shepherds quake at the sight;
Glories stream from heaven afar,
Heavenly hosts sing Alleluia!
Christ the Savior is born,
Christ the Savior is born!

Silent night, holy night,
Son of God, love’s pure light;
Radiant beams from Thy holy face
With the dawn of redeeming grace,
Jesus, Lord, at Thy birth,
Jesus, Lord, at Thy birth.

Silent night, holy night
Wondrous star, lend thy light;
With the angels let us sing,
Alleluia to our King;
Christ the Savior is born,
Christ the Savior is born!

-----

To see and hear more on the "Stille Nacht" visit this page of "The Cyber Hymnal" - http://www.cyberhymnal.org/non/de/stillena.htm

To see and hear more on the " Silent Night" visit this page of "The Cyber Hymnal" - http://www.cyberhymnal.org/htm/s/i/silntnit.htm

Bill Egan. “Silent Night: The Song Heard ‘Round The World.” Posted on the “SilentNightWeb” - http://silentnight.web.za/history/index.htm

Stille Nacht text in German and English, on the “SilentNightWeb” - http://silentnight.web.za/translate/deu.htm


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Sunday, December 16, 2007

Is a New Solar Cycle Beginning?

For more than a year, the sun has experienced a lull in activity, marking the end of Solar Cycle 23, which peaked with many storms in 2000--2003. Then on Tuesday, December 11, the orbiting Solar and Heliospheric Observatory (SOHO) spotted a small knot of magnetism that popped over the sun's eastern limb at latitude 24 degrees North. What's more, the field was magnetically reversed. These observations excited scientist because they might indicate the beginning of the next solar cycle.

Old cycle spots congregate near the sun's equator, or 0 degrees latitude. But new solar cycles always begin with a high-latitude (around 25 or 30 degrees), reversed polarity sunspot--a sunspot with magnetic polarity opposite to that of the previous solar cycle.

However, there was no sunspot. So far the region has been just a bright knot of magnetic fields. If these fields do coalesce into a dark sunspot, scientists will announce that Solar Cycle 24 has officially begun.

Many forecasters believe Solar Cycle 24 will be big and intense. Starting slow and peaking in 2011 or 2012, the cycle to come could have significant impacts on telecommunications, air traffic, power grids and GPS systems, as well as creating some spectacular auroras.

To learn more about the Solar and Heliospheric Observatory (SOHO), its mission and observations, visit the mission home page: http://sohowww.nascom.nasa.gov/


The Rings of Saturn as Old as the Solar System?

Saturn's rings were probably created as the solar system was being built around 4.5 billion years back, according to scientists.

The scientists in the United States have carried out a study, using data collected by NASA's Cassini spacecraft, and found that rather than being formed 100 million years ago, the rings are created when the solar system was under construction.

Data from NASA's Voyager spacecraft in the 1970s and later the Hubble Space Telescope led the scientists to believe that Saturn's rings were relatively young and likely created by a comet that shattered a large moon.

"Ring features seen by instruments on Cassini - which arrived at Saturn in 2004 - indicate the rings are not formed by a single cataclysmic event. The ages of the different rings appear to vary significantly and the ring material is being continually recycled.

"The evidence is consistent with the picture that Saturn has had rings all through its history. We see extensive, rapid recycling of ring material, in which moons are continually shattered into ring particles, which then gather together and re-form moons.

"We have discovered that the rings were probably not created just yesterday in cosmic time, and in this scenario it is not just luck that we are seeing planetary rings now. They probably were always around but continually changing, and they will be around for many billions of years," according to Prof Larry Esposito, the Principal Investigator for Cassini's Ultraviolet Imaging Spectrograph at CU-Boulder.

To learn more, visit the Cassini mission home pages: http://saturn.jpl.nasa.gov and
http://www.nasa.gov/cassini


Voyagers 1 and 2 Still Expanding Our Knowledge of Space

NASA's Voyagers 1 and 2, launched 30 years ago, were scheduled to work for five years. They are expected to continue sending back information from a limited number of instruments until 2020.
The Voyagers have had more public fame than most unmanned NASA spacecraft, in great part due to the messages and cultural artifacts that they carry in the event they encounter extraterrestrial life. Each has a "golden record" that contains sounds (including greetings in several languages and music, including Chuck Berry's "Johnny B. Goode") and images (including a solar system map and a picture of people eating, licking and drinking).
Driver/Transportation

NASA’s Voyager 2 spacecraft recently broke through the edge of the bubble of solar wind that radiates from our sun, where the transition to interstellar space begins.

By crashing this turbulent border, known as the solar wind termination shock, while nearly 1 billion miles closer to the sun than where Voyager 1 struck it, mission scientists say Voyager 2 showed this solar-wind bubble — the heliosphere — is irregularly shaped.

This border shock area is formed when the solar wind is abruptly slowed by pressure from the gas and magnetic field of interstellar space, according to University of Arizona scientist J. Randy Jokipii, a Voyager science team member and Regents' professor.

The twin spacecraft, launched in the summer of 1977, are many billions of miles apart.
The area between the solar system's bubble and true interstellar space may take 10 years to cross, according to Jokipii.

Jokipii was one of several Voyager science team members who made presentations on Voyager 2's most recent data earlier this week at the 2007 fall meeting of the American Geophysical Union in San Francisco.

Team members said Voyager 2's instruments showed that it crossed the shock area several times, proving the edge "sloshes" back and forth, like surf on the beach.

Voyager 2 is so far out that its radioed datagrams to scientists back on Earth take more than 13 hours to arrive.

As the plutonium in the spacecrafts' nuclear-power generators degrades they produce less power, and equipment has been turned off.

The Voyagers are expected to function and send back data from their reduced instrumentation until 2020, well over 40 years after they were launched.

Once the spacecraft cross the zone between the heliosphere and true interstellar space, Jokipii said, "The Voyagers' detectors will be the first to detect interstellar matter, magnetic fields and energetic particles. This will tell us a great deal about the system's local space environment."

To learn more about this discovery and the current missions of NASA’s Voyager 1 and 2 spacecraft, visit their website: http://voyager.jpl.nasa.gov


Course Change to Comet Hartley 2

On December 13, NASA announced the retargeting of the EPOXI mission for a flyby of comet Hartley 2 on October 11, 2010. Hartley 2 was chosen as EPOXI's destination after the initial target, comet Boethin, could no longer be found. Scientists think comet Boethin may have broken into pieces too small to be located.

The EPOXI mission combines two exciting science investigations -- the Extrasolar Planet Observation and Characterization and the Deep Impact Extended Investigation (abbreviated "EPOXI"). Both investigations will be performed using the Deep Impact spacecraft.

Periodic Comet Hartley 2, also known as 103P/Hartley and 1991t, was the backup flyby choice for comet Boethin. Hartley 2 was discovered on March 15, 1986 by Malcolm Hartley at the Schmidt Telescope Unit in Siding Spring, Australia. Its estimated diameter is 1.6km and its orbital characteristics are as follows: Perihelion distance: 1.03 AU; Semi-major axis: 3.45; Eccentricity: 0.699; Orbital period: 6.41 years; Last perihelion: 2004.

The spacecraft's closest approach to the comet will be about 620 miles. The spacecraft will use the same two science instruments it used during the prime mission to guide an impactor into comet Tempel 1 in July 2005. If EPOXI's observations of Hartley 2 show it is similar to one of the other comets that have been observed, this new class of comets will be defined for the first time. If the comet displays different characteristics, it would deepen the mystery of cometary diversity.

In addition to investigating comet Hartley 2, the spacecraft will use the larger of its two telescopes, beginning in late January 2008, to observe several previously discovered nearby extrasolar planetary systems. It will study the physical properties of giant planets and search for rings, moons and planets as small as three Earth masses. It also will look at Earth as though it were an extrasolar planet to provide data that could become the standard for characterizing these types of planets.

Mission controllers at JPL began directing EPOXI towards Hartley 2 on November 1. They commanded the spacecraft to perform a three-minute rocket burn that changed the spacecraft's velocity. EPOXI's new trajectory sets the stage for three Earth flybys, the first on December 31, 2007. This will place the spacecraft into an orbital "holding pattern" until time for the optimal encounter of comet Hartley 2 in 2010.

EPOXI's low mission cost of $40 million is achieved by taking advantage of the existing Deep Impact spacecraft.

For information about EPOXI, visit: http://www.nasa.gov/epoxi


Extrasolar Planet Gliese 581 D Might Be Habitable

In April, a European team announced the discovery of two new planets orbiting the star Gliese 581. Gliese 581 (pronounced “Gleez”) is a type M2.5V red dwarf star located 20.4 light years away in the constellation Libra. The two planets, the fourth and fifth discoveries around the parent star, had masses at 5 and 8 times that of Earth. Given their distance to their star, these new planets, now known as Gliese 581c and Gliese 581d, were the first ever possible candidates for habitable planets.

The journal Astronomy & Astrophysics has just published two theoretical studies of the Gliese 581 planetary system. Two international teams, one led by Franck Selsis and the other by Werner von Bloh, investigated the possible habitability of these two super-Earths from two different points of view. To do this, they estimated the boundaries of the habitable zone around Gliese 581, that is, how close and how far from this star liquid water can exist on the surface of a planet.

Both teams found that, while Gliese 581 c is too close to the star to be habitable, the planet Gliese 581 d might be habitable. However, the environmental conditions on planet d might be too harsh to allow complex life to appear. Planet d is tidally locked, like the Moon in our Earth-Moon system, meaning that one side of the planet is permanently dark. Thus, strong winds may be caused by the temperature difference between the day and night sides of the planet. Since the planet is located at the outer edge of the habitable zone, life forms would have to grow with reduced stellar irradiation and a very peculiar climate.

In any case, both studies definitely confirmed that Gliese 581c and Gliese 581d will be prime targets for the future ESA/NASA space mission Darwin/Terrestrial Planet Finder (TPF), dedicated to the search for life on Earth-like planets. These space observatories will make it possible to determine the properties of their atmospheres.


Red Sunset Apparently Observed on an Extrasolar Planet

For the first time, astronomers have spotted what looks like a sunset on a planet outside our solar system. Using the Hubble Space Telescope, they detected traces of a red haze surrounding a Jupiter-like ball of hot gas circling a star in the northern sky 63 light-years — 370 trillion miles — from Earth.

The haze is similar to the thick atmospheres around Venus and Titan, Saturn’s largest moon, said Frederic Pont, an astronomer at the Geneva Observatory in Switzerland, who led the discovery team.

The discovery is another step in the quest to find an Earth-like planet that could support life. NASA is planning space missions to detect such objects.

Since 1995, astronomers have detected 268 extrasolar planets orbiting 230 stars. Some form miniature solar systems that contain as many as five planets. So far, none is a cool, rocky planet like Earth, and none is thought capable of supporting life.

Pont’s planet — with the scientific name HD 189733b — was discovered in 2005 in one of its frequent passes in front of its star. As it crossed the star’s disk, it briefly dimmed the light reaching Earth. The dimming, about 3 percent, was repeated every 2.2 days as the planet whirled around its host. The star is about three-quarters the size of our sun. It is in the faint constellation Vulpecula (“little fox”).

The haze was discovered because gases in a planet’s atmosphere affect the color of starlight as it passes through on its way to Earth. The red light from this planet revealed traces of iron, silicate and aluminum oxide, the sources of rubies and sapphires.

In July, British researchers using NASA’s Spitzer Space Telescope reported finding signs of water vapor in the same planet’s atmosphere. Pont’s group detected no such evidence.
However, an American astronomer, Travis Barman of the Lowell Observatory in Flagstaff, Ariz., in April reported definite signs of water vapor in the atmosphere of a different planet 150 light-years — 880 trillion miles — away in the constellation Pegasus.

That planet, nicknamed Osiris, for the Egyptian god of the dead, has oxygen, carbon and hydrogen as well as water in its atmosphere. It is about 1.3 times bigger than Jupiter and orbits its star every 3.5 days at a distance of 4 million miles, much closer than Mercury is to the sun. Its temperature, almost 2,000 degrees Fahrenheit, makes it uninhabitable for any form of life known on Earth.

The planet in Vulpecula is about 1.25 times bigger than Jupiter. It’s only 3 million miles from its star, and its temperature, about 1,700 degrees Fahrenheit, is also far too hot for life as we know it.

To learn more about extrasolar planets, visit NASA’s PlanetQuest website: http://planetquest.jpl.nasa.gov


XMM-Newton Unveils Hidden Cosmic Giant

For years astronomers could not understand the relation of two equally bright and large X-ray regions in the cluster of galaxies known as Abell 3128. Now they understand. Astronomers from SRON Netherlands Institute for Space Research have discovered a new cluster of galaxies, hidden behind a previously identified cluster of galaxies. The new cluster is apparently just as bright as the first group, but is six times further away. The astronomers made the discovery as part of an international team using the space telescope XMM-Newton.

Clusters of galaxies are the largest structures in the universe. They consist of tens to hundreds of massive galaxies, of which each in turn consists of hundreds of billions of stars. Gravity is the binding factor. The hot gas of tens of millions degrees Celsius, present in the clusters, emits X-rays, which renders the cluster visible for space telescopes such as XMM-Newton. Detailed analyses of these X-rays tell astronomers more about the composition of the gas and accordingly, its origin.

What was so intriguing about the two X-ray spots in cluster Abell 3128 was the fact that although they had the same size and brightness, the gas clouds seemed to have completely different compositions. While one spot was clearly caused by a hot gas cloud rich in metals released by supernova explosions in the galaxies, the other spot seemed to contain a much lower amount of metals than any other cluster previously observed.

The observations with the XMM-Newton made the surprise complete. The gas cloud behind the puzzling X-ray spot was found to be 4.6 billion light years away, at least six times further than cluster Abell 3128.

The research of large cluster of galaxies mainly centers on the question as to how the large structures of the universe formed. According to current insights, material is spread throughout the universe as a web of thread-like structures of rarefied hot gas: the cosmic web. Between these threads are cavities that are becoming increasingly larger as the universe expands. The structure is often compared to clusters of soap bubbles. The density of the material is highest at the intersections in the web. Therefore that is where clusters of galaxies develop.

XMM-Newton is the X-ray telescope of the European Space Agency (ESA) for which SRON built an instrument capable of analyzing the X-rays in detail. XMM-Newton was launched in 1999 from French Guyana and still functions superbly. ESA recently extended the operation of the satellite for a further 5 years.

To learn more about XMM-Newton, visit these websites:

XMM-Newton Science Operations Centre – http://xmm.vilspa.esa.es/
XMM-Newton Education and Public Outreach – http://xmm.sonoma.edu/


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MARS IS COMING, PART 7

With only a few days before Mars’ closest approach to Earth on December 18/19 and opposition with Earth coming on December 24, please enjoy your next installment on the Red Planet Mars.


Surface Features, Part 2

The northern plains have remarkably little relief. They encompass all of the terrain within 30° of the pole except for the layered terrains immediately around the pole. Three broad lobes extend to lower latitudes. These include Chryse Planitia and Acidalia Planitia (centered on 30° W longitude), Amazonis Planitia (160° W), and Utopia Planitia (250° W). The only significant relief in this huge area is a large ancient impact basin, informally called the Utopia basin (40° N, 250° W).

Several different types of terrain have been recognized within the plains. In knobby terrain, numerous small hills are separated by smooth plains. The hills appear to be remnants of an ancient cratered surface that is now almost completely buried by younger material that forms the plains. Various plains have a polygonal fracture pattern that resembles landforms found in permafrost regions on Earth. Others have a peculiar thumbprint-like texture.

The origin of the low-lying northern plains remains controversial. Some scientists suggest they were formerly occupied by ocean-sized bodies of water that were fed by large floods. Others have seen little evidence of global-sized bodies of water and have noted the difficulty of explaining the disappearance of such large water volumes.

Large flood channels, termed outflow channels, are observed to be cut into the Martian surface in several areas. The channels are generally tens of kilometers across and hundreds of kilometers long. Most emerge full-size from rubble-filled depressions and continue downward into the northern plains or the Hellas basin in the south. Many of the largest channels drain from the south and west into Chryse Planitia. These are true channels in that they were once completely filled with flowing water, as opposed to most river valleys, which have never been close to full but contain a much smaller river channel. The peak discharges of the floods that cut the channels are estimated to have been a hundred to a thousand times the peak discharge of the Mississippi River—truly enormous events. Some of the floods appear to have formed by catastrophic release of water from lakes. Others formed by explosive eruption of groundwater.

Close to the equator, centered on 70° W longitude, are several interconnected canyons collectively called Valles Marineris. Individual canyons are roughly 200 km (125 miles) across. At the center of the system, several canyons merge to form a depression 600 km (375 miles) across and as much as 9 km (5.6 miles) deep—about five times the depth of the Grand Canyon. The entire system is more than 4,000 km (2,500 miles) in length, or about 20 percent of Mars's circumference. At several places within the canyons are thick sedimentary sequences, which suggest that lakes may have formerly occupied the canyons. Some of the lakes may have drained catastrophically to the east to form large outflow channels that start at the canyons' eastern end. How the canyons formed is not known, but faulting probably played a major role.

The canyons of Valles Marineris terminate to the west near the crest of the Tharsis rise, a vast bulge on the Martian surface more than 8,000 km (5,000 miles) across and 8 km (5 miles) high at its center. Near the top of the rise are three of the planet's largest volcanoes—Ascraeus Mons, Arsia Mons, and Pavonis Mons—which tower 18, 17, and 14 km (11.2, 10.5, and 8.7 miles), respectively, above the mean radius. Just off the rise to the northwest is the planet's tallest volcano, Olympus Mons, and at the north end is yet another large volcano, Alba Patera, which approaches 7 km (4.3 miles) in height. Between these giant landforms are several smaller volcanoes and lava plains. What formed Tharsis is not known; it may have resulted from a combination of uplift and the accumulation of huge volumes of volcanic deposits.

The presence of the Tharsis rise has caused stresses within, and deformation of, the crust. A vast system of fractures radiating from Tharsis and compressional ridges arrayed around the rise are evidence of this process. The radial faulting around Tharsis appears to have contributed to the formation of the Valles Marineris system.

Another volcanic rise is located in the northern region of Elysium at about 215° W longitude. Much smaller than Tharsis, being only 2,000 km (1,200 miles) across and 6 km (3.7 miles) high, the Elysium rise is also the site of several volcanoes.


Next Time: "The Interior, Martian Meteorites and Martian Moons"


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


Dec 16 – the Moon Occults Asteroid 2 Pallas

Dec 16 – the planet Uranus is 2° south of Moon

Dec 17, 5:18 A.M ET - First Quarter Moon

Dec 17 – the planet Mercury is in superior conjunction

Dec 18 – the planet Mars closest approach for the current apparition (0.589 AU)

Dec 20 – the planet Saturn stationary. The body appears motionless in the sky due to the turning point between its direct and retrograde motion.

Dec 20 – the dwarf planet Pluto is in conjunction with the Sun

Dec 22, 1:08 A.M. ET (06:08 UT) - Winter solstice for the northern hemisphere (Summer solstice for the southern hemisphere)

Dec 22 – the Moon is at perigee, the point in the Moon's orbit when it is nearest to Earth

Dec 22 – Peak of the Ursid meteor shower. This shower is caused by dust from Comet P/Tuttle, also known as Comet 1790 II. The comet was originally found by French astronomer Pierre Méchain in 1790, and rediscovered by Horace Tuttle of the Harvard Observatory in 1858. This comet has a period of 13.7 years. Meteors from the Ursid shower may be visible from December 17 through 25 with the peak occurring December 21/22. The Ursid meteor rate is not spectacular, averaging only 5 per hour. The meteors will appear to originate from a point near the star Beta Ursae in the middle of the constellation Ursa Major (RA 14hrs 28min, Dec +76°) in the northern sky.


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THIS WEEK IN HISTORY

Dec 16, 1826 – Birthday of Italian astronomer Giovanni Battista Donati (1826 – 1873)

Dec 16, 1857 – 150th birthday of American astronomer Edward Emerson Barnard (1857 – 1923), said to be one of the greatest observational astronomers.

Dec 16, 1917 – 90th birthday of American author Arthur C. Clarke (Happy Birthday, Arthur!)

Dec 16, 1965 – Launch of Pioneer 6 (Sun Orbiter)

Dec 16, 1994 - Discovery of QUE 94201 (a Mars Meteorite)

Dec 19, 1960 – Suborbital launch of Mercury 1 (unmanned)

Dec 20, 1904 – Birthday of Mount Wilson Observatory

Dec 20, 1939 – Birthday of Ames Research Center (http://www.arc.nasa.gov/)

Dec 21, 1984 – Launch of Vega 2 Launch (Soviet Venus/Comet Halley Mission)

Dec 21, 1966 – Launch of Luna 13 (USSR Moon Lander)


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MUSICAL DIVERSION

It has been suggested that during the Christmas seasons of 15th-century England, it was not uncommon for patrolling town watchmen to sing carols and to wish good health to the nobility and landowners whom they passed, in an effort to earn a little extra money. Their greeting might have been something similar to "God keep you strong, gentlemen." Of course, it would not have sounded quite like that in the English language of the day. For example, to keep or hold something would have meant to "rest" it, and to be strong or mighty would have meant to be "merry." So the watchman's greeting would have actually been something closer to "God rest ye merry, gentlemen." The song may have been lengthened over time, by different singers and by different generations, with the adding of the Christmas story and of other good wishes.

So may have been the birth of one of the oldest known Christmas carols. The concept of carols came from the common people who wished to express their simple ideas and honest feelings that were not expressed by the somber music of the organized church. The word "carol" derives from the French word caroller, meaning to dance around in a circle. The word meaning eventually came to also include music and lyrics. There were carols for all occasions, with Christmas carols relating, for the most part, to the birth of Jesus. It is said that Christmas carols were first brought into church services in the 12th century by St Francis of Assisi. By the 14th century, the tradition of carol singing and dancing was firmly established throughout Europe. The Protestant reformation came during 16th century, and it was during this time that the first versions of many of today's carols were written.

Then in the 17th century came England's "Cultural Revolution" during the war to topple King Charles I (1601 – 1649). The Puritan English Parliament of 1647 officially abolished the celebration of Christmas and all other festivals, as well as the lively music that went with them. Since they were not performed and passed on, many old Christmas carols were lost during this time. It was not until after the fall of the staunch Protestant Oliver Cromwell (1599 – 1658) that Christmas became legal again.

Christmas carols finally became popular again during the lifetime of Queen Victoria (1819 - 1901), when they again expressed joyful and merry themes in their lyrics. As religious observances in the United States and England were closely linked the popularity of Christmas carols grew in both countries in the 19th century.

The revival and perpetuation of the Christmas carol began in 1822 when collections of old songs were published. A record of these carols was preserved in 1823 when British writer and satirist William Hone (1780 – 1842) published a “List of Christmas Carols now annually printed” in is book, “Ancient Mysteries Described.” Later, in 1833, came another surge of carol music by British solicitor and antiquarian William B. Sandys (1792 – 1874). That year, Sandys (pronounced “Sands”), published a carol collection entitled "Christmas Carols Ancient and Modern” (London, Richard Beckley, 1833) and it was in this collection that "God Rest Ye Merry, Gentlemen" first appeared in print. Other carols that first appeared in this collection include "The First Nowell", "I Saw Three Ships Come Sailing In", "God Bless the Master of This House", "Hark the Herald Angels Sing". It has been suggested that the carol “God Rest Ye Merry, Gentlemen” owes its durability to the way its first verse so plainly expresses the essence of the Christmas story.


God Rest Ye Merry, Gentlemen

God rest ye merry, gentlemen, let nothing you dismay,
Remember Christ our Savior was born on Christmas Day;
To save us all from Satan’s power when we were gone astray.

Chorus:

O tidings of comfort and joy, comfort and joy;
O tidings of comfort and joy.

In Bethlehem, in Israel, this blessèd Babe was born,
And laid within a manger upon this blessèd morn;
The which His mother Mary did nothing take in scorn.

(chorus)

From God our heavenly Father a blessèd angel came;
And unto certain shepherds brought tidings of the same;
How that in Bethlehem was born the Son of God by name.

(chorus)

“Fear not, then,” said the angel, “Let nothing you afright
This day is born a Savior of a pure Virgin bright,
To free all those who trust in Him from Satan’s power and might.”

(chorus)

The shepherds at those tidings rejoiced much in mind,
And left their flocks a-feeding in tempest, storm and wind,
And went to Bethl’em straightaway this blessèd Babe to find.

(chorus)

But when to Bethlehem they came where our dear Savior lay,
They found Him in a manger where oxen feed on hay;
His mother Mary kneeling unto the Lord did pray.

(chorus)

Now to the Lord sing praises all you within this place,
And with true love and brotherhood each other now embrace;
This holy tide of Christmas all others doth deface.

(chorus)

God bless the ruler of this house, and send him long to reign,
And many a merry Christmas may live to see again;
Among your friends and kindred that live both far and near—

That God send you a happy new year, happy new year,
And God send you a happy new year.

-----


To see and hear more on the "God Rest Ye Merry, Gentlemen" visit this page of "The Cyber Hymnal" - http://www.cyberhymnal.org/htm/g/o/godrest.htm

"God Rest Ye Merry, Gentlemen" on the "Christmas Carols" Website - http://www.carols.org.uk/god_rest_ye_merry_gentlemen.htm

To learn more about the carol "God Rest Ye Merry, Gentlemen,” visit this article in Wikipeida: http://en.wikipedia.org/wiki/God_Rest_Ye_Merry_Gentlemen

Visit this web page of “Thanks Much” to learn more about the history, lyrics and collect a downloadable MP3 file of "God Rest Ye Merry, Gentlemen" - http://www.thanksmuch.com/christmas/god-rest-ye-merry-gentleman-mp3.html


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Sunday, December 09, 2007

Electronic Observing Aid

MARS member Craig MacDougal came across an interesting snail mail that other members might like to review. It concerns an electronic device to assist those who record video of their observing sessions. It is a box that inserts a time display into the video signal using a GPS device (not included) as its time source. It would be good for occultations, eclipses and the like. Craig scanned both sides of the brochure and place them as JPEG files on his web space.

Here is page 1:

http://mysite.verizon.net/macdouc/osd0001.jpg

…And here is page 2:

http://mysite.verizon.net/macdouc/osd0002.jpg

Please check it out!

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MARS IS COMING, PART 6

Just as a reminder, Mars will be closest to Earth on December 18/19 and will finally reach opposition with Earth on December 24. As we anticipate these dates please enjoy the next installment on the Red Planet Mars.


Surface Features, Part 1

We know about the character of the Martian terrain from spacecraft photography and altimetry. The Viking orbiters imaged the entire planet at a resolution of roughly 250 meters (820 feet) and selected areas at resolutions down to 10 meters (33 feet). Later the Mars Global Surveyor spacecraft imaged selected areas with resolutions of 1.4 meters (4.6 feet), but it covered only a small fraction of the planet. However, the topography of the Martian surface was determined very accurately with the laser altimeter aboard Mars Global Surveyor, which mapped elevations with a vertical resolution of a few meters.

Despite its small size, Mars has a greater range of elevation than Earth. The lowest point on the planet, within the Hellas impact basin, is 8 km (5 miles) below the reference level. The highest point, at the summit of the volcano Olympus Mons, is 21 km (13 miles) above the reference level. So the elevation range is 29 km (18 miles), compared with about 20 km (12.4 miles) on Earth (or, from the bottom of the Mariana Trench to the top of Mount Everest). Because Mars has no oceans, a reference level for elevations had to be defined in terms other than sea level. At first, in the early 1970s, the elevation at which the atmospheric pressure is 6.l millibars (about 0.006 of the sea-level pressure on Earth) was set as the reference. Later, when Mars Global Surveyor acquired more accurate elevation data, a better reference was needed, and the planet's mean radius of 3,389.51 km (2,106.14 miles) was chosen.

As we noted in our first installment, one of the most striking aspects of the Martian surface is the contrast between the southern and northern hemispheres. Most of the southern hemisphere is upland and heavily cratered, resembling the battered highlands of the Moon. Most of the northern hemisphere is lowland and volcanic with few craters. The difference in mean elevation between the two hemispheres is roughly 6 km (3.7 miles). The topographic boundary between the hemispheres is not at the equator but in a very jagged line around 30° north latitude. In some places the boundary is broad and irregular; in other places there are steep cliffs. Some of the most intensely eroded areas on Mars occur along the boundary. Landforms there include outflow channels, areas of collapse called chaotic terrain, and an enigmatic mix of valleys and ridges known as fretted terrain. Straddling the two hemispheres on one side of the planet is the Tharsis rise, a vast volcanic dome standing 8 km (5 miles) above Mars's mean radius, 12 km (7.5 miles) above the northern plains, and more than 2 km (1.2 miles) above the surrounding cratered southern highlands. On or near the Tharsis rise are the planet's largest volcanoes (see the section Tharsis and Elysium, below). Conspicuously absent in either hemisphere are the types of landforms that on Earth result from plate tectonics—for example, long linear mountain chains similar to the Andes, oceanic trenches, or a global system of interconnected ridges.

The reason for the differences between the hemispheres is one of many unexplained Martian mysteries—it may have formed when one or more large asteroids collided with Mars early in its history or as a result of internal changes that occurred when the planetary core formed. Gravity data acquired by Mars Global Surveyor suggests that the Martian crust is much thicker under the southern highlands than under the northern plains.

The number of very large craters in the southern highlands implies the surface is very, very old. Planetary scientists have established from lunar samples returned by Apollo missions that the rate of large asteroid impacts on the Moon declined rapidly between 3.8 billion and 3.5 billion years ago. Surfaces that formed before this time are heavily cratered; those that formed after are less so. Mars very likely had a similar cratering history. Thus, the southern highlands probably formed more than 3.5 billion years ago.

The southern terrain has many different types of craters—huge impact basins; large, partially filled craters with shallow, flat floors and eroded rims; smaller, fresh-looking bowl-shaped craters like those on the Moon; and rampart and pedestal craters. Hellas is the largest impact basin on Mars. According to Mars Global Surveyor altimetry data, the feature is about 7,000 km (4,400 miles) across, including the broad elevated ring that surrounds the depression, and 8 km (5 miles) deep—much larger than was previously thought. Most of the craters measuring tens to hundreds of kilometers across are highly eroded. Because larger craters tend to be older than smaller ones, erosion rates on early Mars appear to have been much higher than on later Mars. It is one reason why we think the climate on early Mars was very different from what it was for most of the planet's later history.

Rampart craters and pedestal craters may be unique to Mars. A rampart crater gets its name from the lobes of ejecta—the material thrown out from the crater and extending around it—are bordered with a low ridge, or rampart. So the ejecta apparently flowed across the ground, which may indicate that it had a mudlike consistency. Some scientists have suggested that the mud formed from a mixture of impact debris and water that was present under the surface. Around a pedestal crater, the ejected material forms a steep-sided platform, or pedestal, with the crater situated inside its border. The pedestal appears to have developed when wind carved away the surface layer of the surrounding region while leaving intact that portion protected by the overlying ejecta.

The high-resolution Viking images showed us an additional characteristic of the ancient southern terrain—the many networks of small valleys that look like the terrestrial drainage systems that are created by flowing water. Examples include Nirgal Vallis, located in the southern hemisphere north of the Argyre impact basin, and Nanedi Vallis, located just north of the equator near the east end of Valles Marineris. Scientists have suggested two alternative methods for their formation, either the runoff of rainfall on the surface or erosion by the outflow of groundwater that seeped onto the surface. In either case, warm climatic conditions may have been required for their formation. A major surprise of the Mars Global Surveyor mission was the observation of small, fresh-appearing gullies on steep slopes at high latitudes. These features look very much like water-worn gullies in Earth's desert regions, but their origin is still hotly debated. Although the discoverers initially proposed they were caused by water erosion, this was challenged by other researchers.

Next time: “Surface Features, 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


Dec 12 – the Moon occults Asteroid 4 Vesta

Dec 13 – Peak of the Geminid meteor shower

Dec 14 – the Moon occults the planet Neptune


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THIS WEEK IN HISTORY

Dec 10, 1950 – St. Louis meteorite fall, which hit a car

Dec 10, 1974 – Launch of the Helios 1 solar orbiter mission

Dec 10, 1984 – Claxton meteorite fall, hit a mailbox

Dec 10, 1992 – Mihonoseki meteorite fall, 15th anniversary, which fell through the roof of a house in Japan

Dec 10, 1999 – Launch of the X-ray Multi-Mirror Mission (XMM-Newton)

Dec 12, 1961 – Launch of Oscar 1

Dec 12, 1967 – Pioneer 8 launch, 40th anniversary

Dec 12, 2004 – Landing of Mars Exploration Rover “Opportunity”

Dec 13, 1867 – 140th birthday of Kristian Olaf Bernhard Birkeland

Dec 13, 1904 – Birthday of Sir William Hunter McCrea

Dec 13, 1972 – Apollo 17 lifted off from the moon; 35 years since a human walked on the moon

Dec 14, 1546 – Tycho Brahe’s birthday

Dec 14, 1962 – Mariner 2, Venus flyby, 45th anniversary

Dec 15, 1965 – Launch of NASA’s Gemini 6, Earth-orbital mission with astronauts Walter Schirra and Thomas Stafford

Dec 15, 1966 - Audouin Dollfus' discovery of Saturn’s moon Janus

Dec 15, 1970 – Landing of Soviet probe Venera 7 on Venus

Dec 15, 1984 – Launch of Vega 1, the Soviet Venus/Comet Halley mission


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MUSICAL DIVERSION

Bunessan is a small village on the Ross of Mull in the south of the island of Mull on the west coast of Scotland. The village name in Scottish Gaelic is Bun Easain, meaning “Foot of the little waterfall,” referring to a nearby waterfall. The village was originally a small community of farmers that practiced the Scottish farming tradition called crofting. In crofting, the landowner or their tenant, called the crofter, worked their holding, the croft, to make a living from the fruit of the land and the fruit of their labors. In many crofting communities the adjacent crofters practiced different endeavors that complemented and benefited each other. Until the 1900s, Bunessan had a mill, weavers and a small fishing fleet.

Not far from Bunessan, in the crofting community of Ardtun, lived Mary Macdonald (1789 – 1872), the daughter of a Baptist cleric who wrote songs and poetry in her native language of Gaelic. One of her songs told the story of the birth of the baby Jesus, who was foretold by prophets, announced by angels, lord of all, yet sleeping in a humble feed trough. Macdonald set her words to the tune of a traditional Gaelic melody. She called the song “Leanabh an Àigh” (Child in the Manger).


Leanabh an Àigh

Leanabh an àigh, an Leanabh aig Màiri
Rugadh san stàball, Rìgh nan Dùl;
Thàinig do’n fhàsach, dh’fhuiling ’n ar n-àite
Son’ iad an àireamh bhitheas dhà dlùth!

Ged a bhios leanabain aig rìghrean na talmhainn
An greadhnachas garbh is anabarr mùirn,
’S geàrr gus am falbh iad, ’s fasaidh iad anfhann,
An àilleachd ’s an dealbh a’ searg san ùir.

Cha b’ionann ’s an t-Uan thàinig gur fuasgladh
Iriosal, stuama ghluais e’n tùs;
E naomh gun truailleachd, Cruithfhear an t-sluaigh,
Dh’éirich e suas le buaidh o ùir.

Leanabh an àigh, mar dh’aithris na fàidhean;
’S na h-àinglean àrd’, b’e miann an sùl;
’S E ’s airidh air gràdh ’s air urram thoirt dhà
Sona an àireamh bhitheas dhà dlùth.


-----

A few decades later, the song was revived by a fellow Scott, Lachlan Macbean (1853 – 1931). Macbean ed­it­ed The Fife­shire Ad­ver­tis­er, a newspaper in Kirk­cal­dy. In addition to his day job, Macbean had a passion for res­ur­rect­ing nearly for­got­ten Gael­ic songs. One of his published collections, entitled “Songs and Hymns of the Gael” (Ed­in­burgh, Scot­land: 1888) included an English translation of Macdonald’s song of the child in the manger. In her memory, Macbean named the song’s melody “Bunessan,” after the nearby village.


Child in the Manger

Child in the manger, Infant of Mary,
Outcast and Stranger, Lord of all,
Child Who inherits all our transgressions,
All our demerits on Him fall.

Once the most holy Child of salvation
Gently and lowly lived below.
Now as our glorious mighty Redeemer,
See Him victorious o’er each foe.

Prophets foretold Him, Infant of wonder;
Angels behold Him on His throne.
Worthy our Savior of all our praises;
Happy forever are His own.

-----

In 1922, English author Eleanor Farjeon (1881 – 1965) wrote a poem entitled “A Morning Song (For the First Day of Spring). The words were set to the “Bunessan” melody, creating the hymn we know today as “Morning Has Broken.” Though not all of the words are typically sung today, the full text follows.


Morning Has Broken

Morning has broken, like the first morning
Blackbird has spoken, like the first bird
Praise for the singing, praise for the morning
Praise for the springing fresh from the word

Sweet the rain's new fall, sunlit from heaven
Like the first dewfall, on the first grass
Praise for the sweetness of the wet garden
Sprung in completeness where his feet pass

Mine is the sunlight, mine is the morning
Born of the one light, Eden saw play
Praise with elation, praise every morning
God's recreation of the new day

(Below is the second have of Farjeon’s text.)

Cool the gray clouds roll, peaking the mountains,
Gull in her free flight, swooping the skies:
Praise for the mystery misting the morning
Behind the shadow, waiting to shine.

I am the sunrise, warming the heavens,
Spilling my warm glow, over the earth:
Praise for the brightness of this new morning
Filling my spirit with Your great love.

Mine is a turning, mine is a new life;
Mine is a journey closer to You:
Praise for the sweet glimpse caught in a moment,
Joy breathing deeply, dancing in flight.

-----

In 1969, a Jesuit priest, Rev. James Quinn, published a collection of new songs entitled, “New Hymns for All Seasons” (London). One of his songs was set to the “Bunessan” melody. The text, called “St. Patrick’s Breastplate,” is a morning prayer for strength and guidance through the coming day. The song is also called by its first line, “This Day God Gives Me.”


This Day God Gives Me

(St. Patrick's Breastplate)
This day God gives me Strength of high heaven
Sun and Moon shining, Flame in my hearth
Flashing of lightning, Wind in its swiftness,
Deeps of the ocean, Firmness of earth.

This day God sends me Strength as my guardian,
Might to uphold me, Wisdom as guide.
Your eyes are watchful, your ears are list’ning,
Your lips are speaking, Friend at my side.

God’s way is my way, God’s shield is ‘round me,
God’s host defends me, Saving from ill.
Angels of heaven, Drive from me always
All that would harm me, Stand by me still.

Rising I thank you, Mighty and Strong One
King of creation, Giver of rest.
Firmly confessing Threeness of Persons
Oneness of Godhead, Trinity blest.

-----

Today, the Scottish village of Bunessan has a population of roughly 200, and includes surrounding areas of Millbrae, Fountainhead and Ardtun. There is a monument to Mary Macdonald near the village, on the road toward Craignure, just after the Knockan crossroads. The ruins of her house can still be found nearby.


To see and hear more on the hymn, “Leanabh an Àigh,” visit this page of "The Cyber Hymnal" - http://www.cyberhymnal.org/non/gd/leanabh.htm

To see and hear more on the hymn, “Child in the Manger,” visit this page of “The Cyber Hymnal” - http://www.cyberhymnal.org/htm/c/h/childman.htm

To see and hear more on the hymn, “Morning Has Broken,” visit this page of “The Cyber Hymnal” - http://www.allspirit.co.uk/morning.html


To view the text of the hymn, “This Day God Gives Me,” visit this Web page:
http://www.janson.com/info/prayer.html


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