AURORA ALERTS: Did you miss the Northern Lights? Next time get a wake-up call from Space Weather PHONE
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SOLAR FLARE: This morning at 0948 UT, tiny sunspot 1110 unleashed a C1-class solar flare (SDO movie). The sunspot has started to grow and this event could herald a period of higher activity from the region.
ECLIPSE SEASON FOR SDO: NASA's Solar Dynamics Observatory (SDO) is in a geosynchronous orbit around Earth, always hovering directly above a ground station near Las Cruces, New Mexico, where two large dish antennas receive SDO's record-breaking data stream. Most of the time, this is a great place to be; SDO can see the sun and transmit data non-stop. But not now. Ralph Seguin of the Lockheed-Martin Solar and Astrophysics Lab explains: "SDO has entered eclipse season. Around the time of the equinoxes, the spacecraft, Earth, and sun can line up almost perfectly. Once a day for about an hour, Earth blocks SDO's view of the sun." This occasionally produces strange results:
"Now we know," says Seguin, "what it would look like if Jupiter and the sun had a child."
Seriously, this is a composite of multiwavelength images and a magnetogram taken by SDO just as the sun was emerging from its daily blackout. "Magnetograms are computed from a series of images taken over a short time span. The ribbons of color result from Earth's motion across the sun during the series of exposures."
Seguin has prepared a movie showing what an eclipse looks like at one of SDO's extreme ultraviolet wavelengths: click to play. "Eclipse season will be over on Oct. 6th," he says. Meanwhile, stay tuned for strange.
SUNSPOT MIRAGE: Lately, sunspot 1109 has been attracting the attention of sunset sky watchers. When the sun is dimmed by haze and low clouds, the behemoth spot can be seen and photographed as a dark mark on the solar disk. Yesterday evening in San Francisco, the spot got even bigger when it was stretched and distorted by a lovely sunset mirage:
Mila Zinkova took the picture overlooking San Francisco Bay. "The sun and sunspot 1109 were constantly changing shape as the sun set," says Zinkova. "It was wonderful. A small green flash at the end added nicely to the mood." Click here to view the complete sunset sequence.
Sunspot 1109, which stretches more than 100,000 km from end to end, is slowly growing as it transits the solar disk. The forecast calls for another week of sunset sunsets before the region disappears over the sun's western limb.
more images: from Aymen Ibrahem of Miami, Alexandria, Egypt; from Konstantinos Christodoulopoulos of Agioi Theodoroi beach, Korinthia, Greece
Sept. 2010 Northern Lights Gallery
[previous Septembers: 2009, 2008, 2007, 2006, 2005, 2004, 2002, 2001, 2000]
Potentially Hazardous Asteroids (PHAs
) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones
all the time.
On September 28, 2010 there were 1145 potentially hazardous asteroids. Notes: LD means "Lunar Distance." 1 LD = 384,401 km, the distance between Earth and the Moon. 1 LD also equals 0.00256 AU. MAG is the visual magnitude of the asteroid on the date of closest approach.
| ||The official U.S. government space weather bureau |
| ||The first place to look for information about sundogs, pillars, rainbows and related phenomena. |
| ||Researchers call it a "Hubble for the sun." SDO is the most advanced solar observatory ever. |
| ||3D views of the sun from NASA's Solar and Terrestrial Relations Observatory |
| ||Realtime and archival images of the Sun from SOHO. |
| ||from the NOAA Space Environment Center |
| ||from the National Solar Data Analysis Center |