Another Type of Dark Matter?

The above NASA Hubble Space Telescope image shows the distribution of dark matter in the center of the giant galaxy cluster Abell 1689, containing about 1,000 galaxies and trillions of stars. Abell 1689 resides 2.2 billion light-years from Earth. The image was taken in June 2002. Image Credit: NASA/JPL-Caltech/ESA/Institute of Astrophysics of Andalusia, University of Basque Country/JHU

Current cosmological theory suggests that our Galaxy, like others, sits in the middle of a large ball-shaped concentration of dark matter. However, there may be other shapes lurking in this hidden gravitational scaffolding. A paper published May 23rd in Physical Review Letters proposes the existence of an additional type of dark matter having strong interactions that cause it to form into large disk-shaped objects. Such dark disks would presumably overlap or “double” up with the disks of conventional matter in galaxies like the Milky Way.

Models of dark matter typically assume it is composed of a single type of particle. The currently favored candidate is a cold, relatively massive particle that interacts only weakly with other particles, including itself. Such dark matter can account for the velocity distribution of stars observed in galaxies. It also agrees well with data from the cosmic microwave background. But these successes do not exclude contributions from other types of dark matter.

Authors JiJi Fan and colleagues from Harvard University explored adding “partially interacting” particles into the dark matter mix. They estimate that a small fraction (around 5% ) of dark matter—an amount comparable to conventional baryonic matter—may be of this more interacting type. Their model assumes a heavy dark “proton” and a light dark “electron” that interact through a kind of “dark electromagnetism.” Processes such as bremsstrahlung and Compton scattering are efficient enough to allow this small fraction of dark matter to cool down and collapse into disks. Dark disks may be detectable in several ways. For example, their gravitational effects might show up in upcoming star surveys, or cosmic-ray observations could reveal a signature from self-annihilations of dark disk particles.

To learn more, see the following article:

Physical Review Letters 110, 211302 (2013)

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Is Voyager 1 Outside Our Solar Bubble?

This artist's concept shows NASA's Voyager spacecraft against a field of stars in the darkness of space. The two Voyager spacecraft are traveling farther and farther away from Earth, on a journey to interstellar space, and will eventually circle around the center of the Milky Way galaxy. Image Credit: NASA/JPL-Caltech

A newly published paper argues that NASA's Voyager 1 spacecraft has already entered interstellar space. The model described in the paper is new and different from other models used so far to explain the data the spacecraft has been sending back from more than 11 billion miles (18 billion kilometers) away from our sun.

NASA's Voyager project scientist, Ed Stone of the California Institute of Technology in Pasadena, explains: 

"Details of a new model have just been published that lead the scientists who created the model to argue that NASA's Voyager 1 spacecraft data can be consistent with entering interstellar space in 2012. In describing on a fine scale how magnetic field lines from the sun and magnetic field lines from interstellar space can connect to each other, they conclude Voyager 1 has been detecting the interstellar magnetic field since July 27, 2012. Their model would mean that the interstellar magnetic field direction is the same as that which originates from our sun. 

Other models envision the interstellar magnetic field draped around our solar bubble and predict that the direction of the interstellar magnetic field is different from the solar magnetic field inside. By that interpretation, Voyager 1 would still be inside our solar bubble. 

The fine-scale magnetic connection model will become part of the discussion among scientists as they try to reconcile what may be happening on a fine scale with what happens on a larger scale.

The Voyager 1 spacecraft is exploring a region no spacecraft has ever been to before. We will continue to look for any further developments over the coming months and years as Voyager explores an uncharted frontier."

NASA's Jet Propulsion Laboratory, in Pasadena, Calif., built and operates the Voyager spacecraft. California Institute of Technology in Pasadena manages JPL for NASA. The Voyager missions are a part of NASA's Heliophysics System Observatory, sponsored by the Heliophysics Division of the Science Mission Directorate at NASA Headquarters in Washington.

For more information about the Voyager mission, visit: http://www.nasa.gov/voyager and http://voyager.jpl.nasa.gov.

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AR 1589, Most Active for October 11th...

The above image was taken October 11th at 08:04:00 UTC by the Atmospheric Imaging Assembly (AIA), at 131 Angstroms, aboard the Solar Dynamics Observatory (SDO). This was at the time of a C4 x-ray flare near the northeast (upper-left) limb, produced by Active Region 1589 (AR 1589). Image Credit: SDO/AIA

For the end of October 10th and most of October 11th, the solar activity was low. Active Region 1589 (AR 1589), in the northeast quadrant, was responsible for the largest flare of the period; a C4 x-ray flare on the 11th at 08:04 UTC. AR 1589 is currently the most complex region, with a Beta-Gamma magnetic classification. New region AR New Region 1590 rotated onto the southeast limb and was numbered.  No Earth-directed coronal mass ejections were observed. The forecast through October 14th: The solar activity is expected to be low with a chance for isolated M-class activity.

Here at home, the geomagnetic field was quiet.  Solar wind speed, measured at the Advanced Composition Explorer (ACE) spacecraft, was slightly elevated between approximately 440 to 500 km/s while the Bz component of the interplanetary magnetic field did not vary much beyond +/- 4 nT. The greater than 2 MeV electron flux at geosynchronous orbit was at high levels throughout the period. The forecast through October 14th: The geomagnetic field is expected to be mostly quiet on 12th and 13th. On the 14th, a coronal hole high-speed stream is expected to move into geoeffective position, causing quiet to unsettled conditions with a chance for active periods. Stay tuned...

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center (www.swpc.noaa.gov/today.html).

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO) (sdo.gsfc.nasa.gov), the Solar and Heliospheric Observatory (SOHO) (sohowww.nascom.nasa.gov), the Advanced Composition Explorer (ACE) (www.srl.caltech.edu/ACE), and the Solar Terrestrial Relations Observatory (STEREO) (stereo.gsfc.nasa.gov).

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Sol Giving Low-to-Moderate Activity...

The above image was taken October 10th at 05:04:00 UTC by the Atmospheric Imaging Assembly (AIA), at 94 Angstroms, aboard the Solar Dynamics Observatory (SDO). This was at the time of an M1 x-ray flare just beyond the southeastern (lower-left) limb, produced by a yet-to-be-designated region. Image Credit: SDO/AIA

For the end of October 9th and most of October 10th, the solar activity was moderate. A pair of M1 x-ray events were produced on the 9th at 23:31 UTC and on the 10th at 05:04 UTC by a new region which has not yet rotated around the southeast limb. Active Region 1589 (AR 1589), in the northeastern quadrant, remains the largest and most complex group on the solar disk. The forecast through October 13th: The solar activity is expected to be low with the chance for moderate levels.

Above Earth, the geomagnetic field began the period at minor storm conditions, due to the onset of a coronal hole high-speed stream coupled with residual and lingering coronal mass ejection (CME) effects. Mostly quiet conditions then followed and continued for the remainder of the period. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels during the period. The forecast through October 13th: The geomagnetic field is expected to be quiet to unsettled with isolated active levels on the 11th, as coronal hole effects continue. Mostly quiet conditions are forecast for the 12th and 13th. Stay tuned...

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center (www.swpc.noaa.gov/today.html).

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO) (sdo.gsfc.nasa.gov), the Solar and Heliospheric Observatory (SOHO) (sohowww.nascom.nasa.gov), the Advanced Composition Explorer (ACE) (www.srl.caltech.edu/ACE), and the Solar Terrestrial Relations Observatory (STEREO) (stereo.gsfc.nasa.gov).

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B-Class Events from AR 1585...

The above X-ray image of the sun was taken October 7th at 02:44:00 UTC by the Solar X-ray Imager (SXI) aboard the GOES-15 satellite. Image Credit: NOAA

For the end of October 5th and most of October 6th, the solar activity has been at very low levels. Active Region 1585 (AR 1585), in the southeastern quadrant, has been the most active region, producing multiple B-class events. No Earth directed coronal mass ejections (CMEs) were observed. The forecast through October 9th: The solar activity is expected to be at very low to low levels.

Here at home, the geomagnetic field has been at predominantly quiet levels. Solar wind speeds, as measured by the Advanced Composition Explorer (ACE) spacecraft, remain at nominal levels. Even so, energetic particle measurements by the EPAM sensor, indicate a CME is currently traveling toward Earth. The forecast through October 9th: The geomagnetic field is expected to be at predominantly quiet levels on the 7th. An increase to unsettled to active levels with a chance for minor storm periods is expected on the 8th and 9th as the 05 October CME is forecasted to arrive.

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center (www.swpc.noaa.gov/today.html).

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO) (sdo.gsfc.nasa.gov), the Solar and Heliospheric Observatory (SOHO) (sohowww.nascom.nasa.gov), the Advanced Composition Explorer (ACE) (www.srl.caltech.edu/ACE), and the Solar Terrestrial Relations Observatory (STEREO) (stereo.gsfc.nasa.gov).

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Partial Halo CME on October 5th!

The link below presents views of a partial halo coronal mass ejection (CME) using images on October 5th from 06:30:07 UTC through 11:47:19 UTC. The video is compiled of images from the Solar Dynamics Observatory (SDO) and the Solar and Heliospheric Observatory (SOHO). The video was prepared by helioviewer.org and posted to YouTube by contributor "otraLoly." Image Credit: SDO/AIA/SOHO

CLICK HERE TO WATCH THE VIDEO.

For the end of October 4th and most of October 5th, the solar activity was very low.  A long duration (7.5 hours) B7 x-ray event was observed on the 5th at 07:30 UTC. Post eruption loop structures were observed in GOES SXI imagery beginning at approximately 03:28 UTC in the vicinity of Active Region (AR 1584), in the southwest quadrant, shortly after the beginning of the B7 flare at 03:17 UTC. A partial halo coronal mass ejection (CME) was first observed in SOHO/LASCO C3 imagery at 07:30 UTC and STEREO A COR2 imagery at 04:09 UTC with an estimated plane-of-sky speed at 590 km/s. WSA-ENLIL model indicates this Earth-directed CME to become geoeffective late on the 8th. The forecast through October 8th: The solar activity is expected to continue at very low levels with the chance for a C-class flare.

Above Earth, the geomagnetic field was quiet. The forecast through October 8th: The geomagnetic field is expected to be mostly quiet on the 6th and 7th. Late on the 8th, today's CME is expected to affect Earth, causing unsettled to active conditions with a chance for minor storm periods. Stay tuned...

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center (www.swpc.noaa.gov/today.html).

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO) (sdo.gsfc.nasa.gov), the Solar and Heliospheric Observatory (SOHO) (sohowww.nascom.nasa.gov), the Advanced Composition Explorer (ACE) (www.srl.caltech.edu/ACE), and the Solar Terrestrial Relations Observatory (STEREO) (stereo.gsfc.nasa.gov).

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September 5th: More Sleepy Sol...

The above image was taken October 5th at 03:21:04 UTC by the Atmospheric Imaging Assembly (AIA), at 1700 Angstroms, aboard the Solar Dynamics Observatory (SDO). The major sunspot groups visible in this image include Active Region 1585 (left), 1582 (right of center) and 1579 (right). Image Credit: SDO/AIA

For the end of October 3rd and most of October 4th, the solar activity was very low. The forecast through October 7th: The solar activity is expected to be very low with a chance for C-class flares.

Here at home, the geomagnetic field was quiet. The forecast through October 7th: The geomagnetic field is expected to be mostly quiet. Stay tuned...

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center (www.swpc.noaa.gov/today.html).

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO) (sdo.gsfc.nasa.gov), the Solar and Heliospheric Observatory (SOHO) (sohowww.nascom.nasa.gov), the Advanced Composition Explorer (ACE) (www.srl.caltech.edu/ACE), and the Solar Terrestrial Relations Observatory (STEREO) (stereo.gsfc.nasa.gov).

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AR 1582 Visible to Naked Eye at Dawn and Dusk!

The above image was taken October 4th at 02:41:56 UTC by the Atmospheric Imaging Assembly (AIA), at 4500 Angstroms, aboard the Solar Dynamics Observatory (SDO). The major sunspot groups visible in this image include Active Region 1585 (left), 1582 (right of center) and 1579 (right). Image Credit: SDO/AIA

We currently have some large sunspot groups. The largest of these is Active Region 1585 (AR 1585). This particular group is so large that it can be seen from Earth, at dawn and dusk, with just the naked eye!

For the end of October 2nd and most of October 3rd, the solar activity was very low. No significant activity occurred. The forecast through October 6th: The solar activity is expected to range from very low to low.

Above Earth, the geomagnetic field began the current UTC day with an isolated unsettled period due to an extended interval of negative Bz. Otherwise, the field was quiet. The forecast through October 6th: The geomagnetic field is expected to be mostly quiet. Stay tuned...

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center (www.swpc.noaa.gov/today.html).

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO) (sdo.gsfc.nasa.gov), the Solar and Heliospheric Observatory (SOHO) (sohowww.nascom.nasa.gov), the Advanced Composition Explorer (ACE) (www.srl.caltech.edu/ACE), and the Solar Terrestrial Relations Observatory (STEREO) (stereo.gsfc.nasa.gov).

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AR 1584's C1 Flare on October 2nd...

The above image was taken October 2nd at 09:04:00 UTC by the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory (SDO). This was during the time of a C1 solar flare, produced by Active Region 1584 (AR 1584), in the southeast (lower-left) quadrant. The displayed image combined the AIA observations at 94, 131, and 171 Angstroms. Image Credit: SDO/AIA

For the end of October 1st and most of october 2nd, the solar activity was low. Active Region 1584 (AR 1584) produced the largest event, a C1 solar flare on the 2nd at 09:04 UTC. And a new group, AR 1585 (in the southeast quadrant) was numbered. No Earth directed coronal mass ejections (CMEs) were observed. The forecast through October 5th: The solar activity is expected to range from low to very low.

Here at home, the geomagnetic field was quiet. The forecast through October 5th: The geomagnetic field is expected to be mostly quiet. Stay tuned...

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center (www.swpc.noaa.gov/today.html).

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO) (sdo.gsfc.nasa.gov), the Solar and Heliospheric Observatory (SOHO) (sohowww.nascom.nasa.gov), the Advanced Composition Explorer (ACE) (www.srl.caltech.edu/ACE), and the Solar Terrestrial Relations Observatory (STEREO) (stereo.gsfc.nasa.gov).

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AR 1575's C9 Flare on Sept 30th...

The above image was taken September 30th at 23:39:00 UTC by the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory (SDO). This was during the time of a C9 solar x-ray event, produced by Active Region 1575 (AR 1575), beyond the western (right) limb. The displayed image combined the AIA observations at 94, 131, and 171 Angstroms. Image Credit: SDO/AIA

For the end of September 30th and most of October 1st, the solar activity was low. Active Region 1575 (AR 1575), which is now around the west limb, produced several C-class x-ray events, the greatest being a C9 on the 30th at 23:39 UTC. No Earth-directed coronal mass ejections (CMEs) were observed. The forecast through October 4th: The solar activity is expected to be low for the 2nd. Activity is expected to be very low to low on the 3rd and 4th, as the complex or regions near the western extent of the visible solar disk continue beyond the limb.

Above Earth, the geomagnetic field began the period at active levels, as weak CME effects from the previous 24 hours continued in progress. The beginning of the 1st saw an increase to severe storm levels, after a second CME arrived at the Advanced Composition Explorer (ACE) on the 30th around 22:21 UTC with a subsequent Sudden Impulse (SI) to Earths magnetic field (35nT measured at Boulder) at 23:07 UTC. A single major storm period followed, before conditions decreased to active and then again to quiet. The forecast through October 4th: The geomagnetic field is expected to be quiet to unsettled on the 2nd as CME effects wane. The 3rd and 4th should see mostly quiet conditions. Stay tuned...

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center (www.swpc.noaa.gov/today.html).

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO) (sdo.gsfc.nasa.gov), the Solar and Heliospheric Observatory (SOHO) (sohowww.nascom.nasa.gov), the Advanced Composition Explorer (ACE) (www.srl.caltech.edu/ACE), and the Solar Terrestrial Relations Observatory (STEREO) (stereo.gsfc.nasa.gov).

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AR 1583s M1 Flare on Sept 30th...

The above image was taken September 30th at 04:33:00 UTC by the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory (SDO). This was during the time of a M1 solar ex-ray event, produced by Active Region 1583 (AR 1583), on the western (right) limb. The displayed image combined the AIA observations at 94, 131, and 171 Angstroms. Image Credit: SDO/AIA

For the end of September 29th and most of September 30th, the solar activity has been at moderate levels. Active Region 1583 (AR 1583) produced an isolated M1 solar x-ray event on the 30th at 04:33 UTC. AR 1583 had grown rapidly, however it is only hours away from rotating off the solar disk and out of view. The remaining active regions on the disk remained stable, producing a few low level C-class events. New AR 1584 was numbered, and as of this writing, had only produced one low level C-class event. No Earth directed coronal mass ejections (CMEs) were observed. The forecast through October 3rd: The solar activity is expected to be at low levels with a slight chance for continued M-class activity for the 1st and 2nd. A return to low levels is expected on the 3rd, as the active region cluster, located in the northwest quadrant, rotates around the west limb.

Here at home, the geomagnetic field has been at quiet to active levels. The enhanced activity was due to the arrival of a CME from the 27th. On the 30th at around 11:00 UTC, measurements, from the Advanced Composition Explorer (ACE) spacecraft, indicated the arrival of this CME. At 11:38 UTC, a sudden impluse of 15 nT was measured by the Boulder magnetometer, as the CME reached Earth. Solar wind velocities increased very little with this initial phase of the CME, increasing from around 280 - 320 km/s. The total interplanetary magnetic field (IMF) increased as the CME arrived, with sustained periods of negative Bz. However, with the lower than expected solar wind speeds, very little geomagnetic effects have been observed. The forecast through October 3rd: The geomagnetic field is expected to be a quiet to active levels with minor storm periods possible on the 1st, as effects of today's CME continue. Quiet to unsettled levels are expected on the 2nd as CME effects wane. A return to predominantly quiet levels is expected on the 3rd. Stay tuned...

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center (www.swpc.noaa.gov/today.html).

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO) (sdo.gsfc.nasa.gov), the Solar and Heliospheric Observatory (SOHO) (sohowww.nascom.nasa.gov), the Advanced Composition Explorer (ACE) (www.srl.caltech.edu/ACE), and the Solar Terrestrial Relations Observatory (STEREO) (stereo.gsfc.nasa.gov).

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Incoming CME from Sept 28th, Storms Expected

The above X-ray image of the sun was taken September 30th at 03:08:00 UTC by the Solar X-ray Imager (SXI) aboard the GOES-15 satellite. Image Credit: NOAA

For the end of September 28th and most of September 29th, the solar activity was low. Numerous weak C-class events were observed, mostly from Active Regions 1575 and 1577 (AR 1575, AR 1577). New region AR 1583 emerged on the disk as a simple bipolar group. No significant changes were observed elsewhere. No Earth-directed coronal mass ejections (CMEs) were observed during the period. The forecast through October 2nd: The solar activity is expected to be low with a slight chance for M-class activity.

Above Earth, the geomagnetic field was quiet. The Advance Composition Explorer(ACE) satellite measurements indicated a steady decline in wind speed from about 325 km/s to near 275 km/s while the Bz component of the interplanetary magnetic field did not vary much beyond +/- 3 nT. On the 29th at about 01:00 UTC, a solar sector boundary crossing from a negative (toward) to a positive (away) orientation was observed. The forecast through October 2nd: The geomagnetic field activity is expected to be at predominately quiet levels through about midday on the 30th. By late on the 30th, active levels with a chance for minor to major storm periods are expected due to the arrival of the Earth-directed CME observed early on the 28th. On the 1st, continued minor to major storm conditions are expected early in the day, decreasing to mostly quiet to unsettled levels with a chance for isolated active periods as effects from the CME wane. Predominately quiet to unsettled conditions are expected on the 2nd. Stay tuned...

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center (www.swpc.noaa.gov/today.html).

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO) (sdo.gsfc.nasa.gov), the Solar and Heliospheric Observatory (SOHO) (sohowww.nascom.nasa.gov), the Advanced Composition Explorer (ACE) (www.srl.caltech.edu/ACE), and the Solar Terrestrial Relations Observatory (STEREO) (stereo.gsfc.nasa.gov).

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AR 1577 C3 Flare and CME...

The above image was taken September 27th at 23:57:00 UTC by the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory (SDO). This was during the time of a long-duration C3 solar flare, produced by Active Region 1577 (AR 1577), to the west (right) of center. The displayed image combined the AIA observations at 94, 131, and 171 Angstroms. Image Credit: SDO/AIA

For the end of September 27th and most of September 28th, the solar activity was low. Active Region 1577 (AR 1577) produced a long-duration C3 flare on the 27th at 23:57 UTC.  The event began with a filament eruption located northwest of and adjacent to the region with a subsequent dual ribbon flare. Associated with this event was an Earth-directed, asymmetric, full-halo coronal mass ejection (CME) which was first visible in the Solar and Heliospheric Observatory (SOHO) LASCO C2 and C3 imagery on the 28th at 00:18 UTC and 00:30 UTC, respectively. The plane-of-sky speed through both of the instruments' fields averaged 1034 km/s with a computed radial velocity of 872 km/s. Little change was observed following. No other Earth-directed CMEs were observed. The forecast through October 1st: The solar activity is expected to be at low levels with a slight chance for M-class activity.

At home, the geomagnetic field was quiet. The Advanced Composition Explorer (ACE) satellite measurements indicated a steady decline in wind velocity from about 400 km/s to near 325 km/s while the Bz component of the interplanetary magnetic field did not vary much beyond +/- 2 nT.  The greater than 10 MeV proton flux at geosynchronous orbit exceeded threshold on the 28th at 03:00 UTC, reached a maximum of 28 pfu at 04:45 UTC and decayed below threshold at 10:40 UTC. Near the end of September 28th, flux levels were still elevated at about 5 pfu.  This event was believed to be associated with the C3 flare observed late on the 27th. The forecast through October 1st: The geomagnetic field activity is expected to be at predominately quiet levels on the 29th and through midday on the 30th. By late on the 30th, active levels with with a chance for minor to major storm periods are expected due to the arrival of the Earth-directed CME observed early on the 28th. On October 1st, continued minor to major storm conditions are expected early in the day, decreasing to mostly quiet to unsettled levels with isolated active periods as effects from the CME wane. Stay tuned...

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center (www.swpc.noaa.gov/today.html).

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO) (sdo.gsfc.nasa.gov), the Solar and Heliospheric Observatory (SOHO) (sohowww.nascom.nasa.gov), the Advanced Composition Explorer (ACE) (www.srl.caltech.edu/ACE), and the Solar Terrestrial Relations Observatory (STEREO) (stereo.gsfc.nasa.gov).

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C4 Flare on September 27th...

The above image was taken September 27th at 17:20:00 UTC by the Atmospheric Imaging Assembly (AIA), at 94 Angstroms, aboard the Solar Dynamics Observatory (SDO). This was during the time of a C4 solar flare, produced by an undesignated region on the southeastern (lower-left) portion of the sun's disc. Image Credit: SDO/AIA

For the end of September 26th and most of September 27th, the solar activity has been low. The largest solar flare was a C4 on the 27th at 17:20 UTC from an unnumbered region in the southeastern portion of the sun's disc. There are currently 9 numbered sunspot regions visible, but most have remained rather stable and quiet. A non-Earth directed full halo coronal mass ejection (CME) was observed in both STEREO A-B and LASCO imagery. The forecast through September 30th: The solar activity is expected to be at low levels with a slight chance for M-class activity.

Here at home, the geomagnetic field has been quiet. The forecast through September 30th: The geomagnetic field is expected to be predominantly quiet. Stay tuned...

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center (www.swpc.noaa.gov/today.html).

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO) (sdo.gsfc.nasa.gov), the Solar and Heliospheric Observatory (SOHO) (sohowww.nascom.nasa.gov), the Advanced Composition Explorer (ACE) (www.srl.caltech.edu/ACE), and the Solar Terrestrial Relations Observatory (STEREO) (stereo.gsfc.nasa.gov).

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C1 Flare From Newbie AR 1582 on Sept 26th...

The above X-ray image of the sun was taken September 27th at 03:48:00 UTC by the Solar X-ray Imager (SXI) aboard the GOES-15 satellite. Image Credit: NOAA

For the end of September 25th and most of September 26th, the solar activity was low. The new Active Region 1582 (AR 1582) rotated onto the southeast limb and produced the only C-class flare, a long duration C1, on the 26th at 12:40 UTC. No Earth-directed coronal mass ejections (CMEs) were observed. The forecast through September 29th: The solar activity is expected to be at low levels with a slight chance for an M-class flare.

Above earth, the geomagnetic field was quiet. The solar wind speed, measured at the Advanced Composition Explorer (ACE) spacecraft, increased from approximately 320 km/s to 450 km/s while the total magnetic field increased from 5 nT to 9 nT. The forecast through September 29th: The geomagnetic field is expected to be mostly quiet with a slight chance for unsettled periods. There is a slight chance for a greater than 10 MeV proton event. Stay tuned...

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center (www.swpc.noaa.gov/today.html).

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO) (sdo.gsfc.nasa.gov), the Solar and Heliospheric Observatory (SOHO) (sohowww.nascom.nasa.gov), the Advanced Composition Explorer (ACE) (www.srl.caltech.edu/ACE), and the Solar Terrestrial Relations Observatory (STEREO) (stereo.gsfc.nasa.gov).

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AR 1580's C4 Flare on Sept 25th...

The above X-ray image of the sun was taken September 26th at 01:48:00 UTC by the Solar X-ray Imager (SXI) aboard the GOES-15 satellite. Image Credit: NOAA

For the end of September 24th and most of September 25th, the solar activity was low. The largest flare was a C4 flare on the 25th at 17:53 UTC from Active Region 1580 (AR 1580). AR 1581 was designated. No Earth-directed coronal mass ejections (CMEs) were observed. The forecast through September 28th: The solar activity is expected to continue at low levels with a slight chance for M-class flares.

Above Earth, the geomagnetic field was quiet. The forecast through September 28th: The geomagnetic field is expected to continue at mostly quiet conditions.  There is a slight chance for a greater than 10 MeV proton event from active regions rotating around the southeast limb. Stay tuned...

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center (www.swpc.noaa.gov/today.html).

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO) (sdo.gsfc.nasa.gov), the Solar and Heliospheric Observatory (SOHO) (sohowww.nascom.nasa.gov), the Advanced Composition Explorer (ACE) (www.srl.caltech.edu/ACE), and the Solar Terrestrial Relations Observatory (STEREO) (stereo.gsfc.nasa.gov).

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Two C1 Flares on September 24th...

The above image was taken September 24th at 15:42:00 UTC by the Atmospheric Imaging Assembly (AIA), at 94 Angstroms, aboard the Solar Dynamics Observatory (SDO). This was during the time of a C1 solar flare, produced by Active Region 1578 (AR 1578), to the east (left) of center on the disc. Image Credit: SDO/AIA

For the end of September 23rd and most of September 24th, the solar activity was low. The new Active Region 1578 (AR 1578), produced a C1 flare on the 24th at 15:42 UTC. And an undesignated region, just rotating onto the Earth-facing disc, produced a C1 flare on the 24th at 19:31 UTC. Another region rotating onto the southeast limb was designated AR 1579. No Earth-directed coronal mass ejections (CMEs) were observed. The forecast through September 27th: The solar activity is expected to be low with a slight chance for M-class flares.

At home, the geomagnetic field was quiet. The forecast through September 27th: The geomagnetic field is expected to be mostly quiet. On the 26th and 27th, the greater than 10 MeV proton probability increases to a slight chance due to potential activity from active regions rotating around the southeast limb. Stay tuned...

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center (www.swpc.noaa.gov/today.html).

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO) (sdo.gsfc.nasa.gov), the Solar and Heliospheric Observatory (SOHO) (sohowww.nascom.nasa.gov), the Advanced Composition Explorer (ACE) (www.srl.caltech.edu/ACE), and the Solar Terrestrial Relations Observatory (STEREO) (stereo.gsfc.nasa.gov).

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C1 X-Ray Flare on September 23rd!

The linked video presents a collection of images taken on September 23rd from 13:21:55 UTC through 15:49:43 UTC, by the Atmospheric Imaging Assembly (AIA) , at 304 Anstroms, aboard the  Solar Dynamics Observatory (SDO). The images show a long-duration C1 x-ray flare from an area of enhanced emission located behind the east limb. The video was posted to YouTube by contributor "Howyouwoodoo". Image Credit: SDO/AIA

CLICK HERE to watch the video.

For the end of September 22nd and most of September 23rd, the solar activity was low. The largest event was a long-duration C1 x-ray flare on the 23rd at 15:56 UTC from an area of enhanced emission located behind the east limb. Active Region 1577 (AR 1577) gave the most change, developing numerous intermediate sunspots. The remaining regions were quiet and stable. And no Earth-directed coronal mass ejections (CMEs) were observed. The forecast through September 26th: The solar activity is expected to be at low levels with a slight chance for M-class activity as active regions are expected to rotate onto the Earth-facing disc.

Above Earth, the geomagnetic field was at quiet levels.  The Advanced Composition Explorer (ACE) satellite measurements indicated a steady decline in wind speed from about 400 km/s to near 350 km/s while the Bz component of the interplanetary magnetic field did not vary much beyond +/- 4 nT. The forecast through September 26th: The geomagnetic field is expected to be at predominately quiet levels. Stay tuned...

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center (www.swpc.noaa.gov/today.html).

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO) (sdo.gsfc.nasa.gov), the Solar and Heliospheric Observatory (SOHO) (sohowww.nascom.nasa.gov), the Advanced Composition Explorer (ACE) (www.srl.caltech.edu/ACE), and the Solar Terrestrial Relations Observatory (STEREO) (stereo.gsfc.nasa.gov).

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September 21st AR 1573 B8 Flare

The above image was taken September 21st at 12:21:00 UTC by the Atmospheric Imaging Assembly (AIA), at 304 Angstroms, aboard the Solar Dynamics Observatory (SDO). This was during the time of a B8 solar flare, produced by Active Region 1573 (AR 1573) near the center of the disc. Image Credit: SDO/AIA

For the end of September 20th and most of the 21st, the solar activity was very low. The largest x-ray event was a B8 solar flare on the 21st at 12:21 UTC produced by Active Region 1573 (AR 1573). The largest spot group on the solar disc, AR 1575 (1575), remains near 250 millionths in area with a Beta magnetic configuration. Two asymmetrical partial halo coronal mass ejections (CMEs) were observed in the Solar and Heliospheric Observatory (SOHO) LASCO instrument. Both events were determined to be backside sourced, and so are not expected to impact Earth. The forecast through September 24th: The solar activity is expected to be very low to low.

Here at home, the geomagnetic field was quiet, despite the influence of a weak coronal hole (CH) high-speed stream. The forecast through September 24th: The geomagnetic field is expected to be quiet to unsettled for the 22nd as the coronal hole effects wane. Conditions are expected to be mostly quiet for the 23rd and 24th. Stay tuned...

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center (www.swpc.noaa.gov/today.html).

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO) (sdo.gsfc.nasa.gov), the Solar and Heliospheric Observatory (SOHO) (sohowww.nascom.nasa.gov), the Advanced Composition Explorer (ACE) (www.srl.caltech.edu/ACE), and the Solar Terrestrial Relations Observatory (STEREO) (stereo.gsfc.nasa.gov).

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AR 1574's C1 Flare on Sept 20th

The above image was taken September 20th at 11:39:00 UTC by the Atmospheric Imaging Assembly (AIA), at 304 Angstroms, aboard the Solar Dynamics Observatory (SDO). This was during the time of a C1 solar flare, produced by Active Region 1574 (AR 1574) on the southwestern (lower right) limb. Image Credit: SDO/AIA

For the end of September 19th and most of the 20th, the solar activity was low. Active Region 1574 (AR 1574) produced a C1 solar flare on the 20th at 11:39 UTC. And AR 1574 has grown over the period, from a simple unipolar spot to a 4-spot bipolar group. All of the other spotted ARs had little change. No Earth-directed coronal mass ejections (CMEs) were observed. The forecast through September 23rd: The solar activity is expected to be at low levels with a slight chance for M-class activity.

Above Earth, the geomagnetic field was at predominately quiet to unsettled levels with a period of active conditions on the 19th between 21:00 UTC and 24:00 UTC. The period began with wind speeds, as measured at the Advanced Composition Explorer (ACE) spacecraft, steady at 400 km/s while the Bz component of the interplanetary magnetic field (IMF) was mostly south at about -10 nT. At about 23:00 UTC, wind speed and temperature indicated slight increases while IMF Bz began fluctuating between +8 to -6 nT. By the 20th at about 01:00 UTC, the phi angle changed from a positive (away) to a negative (toward) orientation. These changes were all indicative of a co-rotating interaction region in advance of a coronal hole high-speed stream. By the end of the period, wind velocities were steady at about 575 km/s while IMF Bz did not vary much beyond +/- 2 nT. The forecast through September 23rd: The geomagnetic field is expected to be at quiet to unsettled levels with isolated active intervals for the 21st and 22nd as a coronal hole high-speed stream (CH HSS) remains geoeffective. By the 23rd, mostly quiet to unsettled levels are expected as CH HSS effects wane. Stay tuned...

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center (www.swpc.noaa.gov/today.html).

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO) (sdo.gsfc.nasa.gov), the Solar and Heliospheric Observatory (SOHO) (sohowww.nascom.nasa.gov), the Advanced Composition Explorer (ACE) (www.srl.caltech.edu/ACE), and the Solar Terrestrial Relations Observatory (STEREO) (stereo.gsfc.nasa.gov).

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