Hang the Transit of Venus on your wall! Hubble-quality images from NASA's Solar Dynamics Observatory are now available as metallic posters in the Space Weather Store.
| || |
ALMOST-X FLARE: On Oct. 20th at 1814 UT, Earth-orbiting satellites detected a strong M9-class solar flare. The source was a new sunspot, AR1598, emerging over the sun's southeastern limb. NASA's Solar Dynamics Observatory recorded the extreme ultraviolet flash (image), which sent waves of ionization rippling through Earth's upper atmosphere. More flares are in the offing. NOAA forecasters estimate a 40% chance of M-flares and a 10% chance of X-flares during the next 24 hours. Solar flare alerts: text, voice.
ORIONID METEOR UPDATE: The Orionid meteor shower is underway as Earth passes through a stream of debris from Halley's Comet. International meteor counts suggest a broad peak of about 25 meteors per hour centered on Oct. 21st. If the trend holds, sky watchers can expect to see a dozen or so Orionids flitting across the sky every hour after midnight on Oct. 21-22. Got clouds? Try listening for Orionid 'pings' on the realtime meteor radar.
Last night, Oct. 21st, Bill Vaughn photographed this piece of Halley's Comet burning up over Mt. Lemmon, north of Tucson, Arizona:
Realtime Meteor Photo Gallery
METEOR MAKES LANDFALL: A small asteroid that exploded over the San Francisco Bay Area on Oct. 17th, shaking houses with its sonic boom, might have scattered pieces of itself on the ground. That's the conclusion of Peter Jenniskens of the NASA Ames Research Center. He triangulated data from a pair of meteor surveillance cameras to determine the fireball's trajectory, denoted by the black arrow in the map below:
"The asteroid entered at a [relatively slow] speed of 14 km/s. There's a good chance that a fairly large fraction of this rock survived and fell somewhere around the North Bay," says Jenniskens. "Much more accurate results will follow from a comprehensive study of the video records. Now, we hope that someone recovers a meteorite on the ground."
In the map, red dots represent the surveillance cameras Jenniskens used to calculate the trajectory. The black arrow traces the asteroid's path; 85 km and 39 km are the altitudes of the asteroid at the two ends of the arrow. Jenniskens adds that "39 km is not the end point, but the final bit captured by the San Mateo video camera." The disintegrating asteroid continued beyond the tip of the arrow for a possible landfall somewhere north of San Francisco. Stay tuned for updates on the meteorite hunt.
Note: This was not an Orionid.
Realtime Space Weather Photo Gallery
Realtime Aurora Photo Gallery
Realtime Noctilucent Cloud Photo Gallery
[previous years: 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2011]
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 21, 2012 there were 1339 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 |