AURORA ALERTS: Did you miss the Northern Lights? Next time get a wake-up call from Space Weather PHONE
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ASTEROID FLYBY: Newly-discovered asteroid 2010 TD54 will fly by Earth on Tuesday, Oct. 12th, about 46,000 km above the planet's surface. At closest approach, the 7-meter space rock will shine like a 14th magnitude star as it races through the constellations Pisces and Aquarius. Advanced amateur astronomers can track the flight of 2010 TD54 using this ephemeris. There is no danger of a collision.
AURORA WATCH: The solar wind is stirring up geomagnetic storms around the Arctic Circle. High-latitude sky watchers should be alert for auroras after local nightfall on Oct. 11-12th. Images: from Calvin Hall of Palmer, Alaska; from Morten Ross of Sandbukta, Norway
SOLAR ACTIVITY: The sun's atmosphere above sunspot 1112 is criss-crossed by a tangled web of magnetic filaments. At the end of the day on Oct. 10th, one of them erupted. Click on the image to view a movie recorded by NASA's Solar Dynamics Observatory:
Because the blast site was located near the sun's eastern limb, Earth was not in the line of fire. The event should not affect our planet. Future eruptions, however, could. Sunspot 1112 and its unstable network of filaments are turning toward Earth, and the next blast could send something our way. Stay tuned for developments.
more images: from Ingmar Glass of Bavaria, Germany; from Cai-Uso Wohler of Bispingen, Germany; from Larry Alvarez of Flower Mound, Texas
CRESCENT PLANET: Venus is moving between Earth and the sun and, in the process, turning its night side toward us. From the terrestrial point of view, only a thin sliver of Venus remains illuminated. Dennis Put sends this picture of the crescent planet from Brielle, The Netherlands:
"Even modest equipment will allow Venus to be viewed as a crescent disk," says Put. "This image was taken in infrared light using a 9-inch Celestron telescope and a DMK21 camera."
The trick is finding Venus. Because the planet is so close to the sun, it hangs very close to the western horizon after sunset. Any low trees or buildings will block the view. One possibility: look before sunset. Venus is actually bright enough to be seen in blue sky. Sky & Telescope makes the following recommendation: "The time to view Venus is in daylight long before sunset — but don't accidentally sweep up the sun! In mid-afternoon, place your scope in the shadow of a building or other obstacle where you have a clear view of the sky 28° to 21° to the sun's left." Observing from inside a shadow means the sun will be safely hidden while you scan the suggested region of sky for Venus. Try it!
more images: from Mariusz Rudziński of Mirostowice Dolne, Poland; from Stephen Williams of Chabot Space and Science Center, Oakland, California;
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 October 11, 2010 there were 1149 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 |
| ||the underlying science of space weather |