FAST-GROWING SUNSPOT: Sunspot group 1117 more than tripled in size over the weekend: SDO movie. The active region has not yet produced a major eruption, but it is crackling with picturesque B-class solar flares. Stay tuned for updates.
ARCTIC AURORA OUTBURST: Last night, Oct. 24th, an outburst of color bright enough to rival the Moon spread across the skies of Scandinavia. Thilo Bubek sends this picture from the outskirts of Tromsø, Norway:
"The auroras were beautiful," says Bubek. Bright moonlight often overwhelms auroras, but in this case the nearly-full Moon was an asset. "It illuminated the landscape, setting the stage for a nice photo-op."
The source of the display was a high-speed solar wind stream, which hit Earth's magnetic field over the weekend, sparking two days of intermittent polar geomagnetic activity. It could turn into three days: High-latitude sky watchers should be alert for more auroras tonight as the solar wind continues to blow.
UPDATED: October 2010 Aurora Gallery
[previous Octobers: 2009, 2008, 2007, 2006, 2004, 2003, 2002, 2001]
SPACE STATION FLYBYS: For the next week, the International Space Station (ISS) will be performing a series of bright evening flybys over North America and Europe. The station is very easy to see if you know when to look. Check the Simple Satellite Tracker for local flyby times or you can turn your cell phone into a field-tested ISS-tracker.
On Oct 21st, amateur astronomer Béla Vingler of Győrújfalu, Hungary, caught the space station flying directly in front of the Moon:
Photo details: 12-inch reflecting telescope, Canon 400D, ISO 800, 1/3200 exp.
The station's winged outline was backlit by the bright debris fields of Crater Tycho as the spacecraft raced across the lunar disk, completing the transit in only a split-second. Because lunar transits happen so fast, careful planning is required to photograph them. The place to start is Calsky.com, which provides precise predictions of ISS transits for locations around the world.
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 25, 2010 there were 1155 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 |