SOLAR FLARES: Fast-growing sunspot 1112 is crackling with solar flares. SDO movies show the three strongest of the past 24 hours: an M3-flare @ 1910 UT on Oct. 16th, a C1-flare @ 0900 UT and another C1-flare @ 1740 UT on Oct. 17th. So far, none of the blasts has hurled a substantial CME toward Earth.
TIME TO SEE COMET HARTLEY: For backyard stargazers, the next few nights are the best time to see green Comet 103P/Hartley 2 as it approaches Earth for an 11-million-mile close encounter on Oct. 20th. Set your alarm for the dark hours before dawn, go outside, and look straight up. You will find Hartley 2 not far from the bright star Capella: sky map. Although the comet is barely visible to the unaided eye, it is easy to find in binoculars and looks great through a backyard telescope.
Last night, English astronomer Nick Howes made a two-hour exposure of the comet using the robotic Faulkes North Telescope in Hawaii:
"The tail now appears to be forking," says Howes. "And with a coma wider than 1o, Comet Hartley is now as impressive as Comet Holmes was in 2007, albeit more diffuse."
Indeed, NASA scientists say 103P/Hartley 2 is one of the most active comets they've seen, with a huge atmosphere and copious outgassing from jets in the nucleus. Amateur astronomers are encouraged to monitor the action and submit their images here.
more images: from Tom Jorgenson of Neenah, Wisconsin; from Yandong Hu of Mt. Wawushan, Jiangsu, China; from Rolando Ligustri using a robotic telescope in New Mexico; from Marian Urbaník of Staškov, Slovak republic; from John Chumack of Dayton, Ohio; from Jan Koeman of Kloetinge, the Netherlands; from Jodi and Roy McCullough of Salem Ohio; from Mike Broussard of Maurice, Louisiana; from Mike Holloway of Van Buren, Arkansas; from Norm Klekoda and Al Bell near Grand Rapids, MI; from Doug Zubenel of Monument Rocks, Gove County, Kansas; from Gregg Ruppel of Ellisville, Missouri
GREAT FILAMENT: A vast filament of magnetism is cutting across the sun's southern hemisphere today. Run a finger along the golden-brown line in this extreme UV image from the Solar Dynamics Observatory and your digit will have traveled more than 400,000 km:
A bright 'hot spot' just north of the filament's midpoint is UV radiation from sunspot 1112. The proximity is no coincidence; the filament appears to be rooted in the sunspot below. If the sunspot flares, it could cause the entire structure to erupt.
UPDATE: Yesterday's M3-flare did not destabilize the filament. Stay tuned, however, because sunspot 1112 is growing and more activity is possible in the hours ahead. Readers with solar telescopes are encouraged to monitor developments.
more images: from Michael Borman of Evansville, Indiana; from Angie Marsh of Hereford, UK; from Matt Wastell of Brisbane, Australia; from Jean-Pierre Brahic of Uzès, France; from John Nassr of Baguio, Philippines; from Peter Chappell of GEO, Sierra de Cadiz, Spain
October 2010 Aurora Gallery
[previous Octobers: 2009, 2008, 2007, 2006, 2004, 2003, 2002, 2001]
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 17, 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 |