Turn your cell phone into a field-tested satellite tracker. Works for Android and iPhone.
| || |
AURORA WATCH: A coronal mass ejection launched from the sun's eastern limb on May 9th could deliver a glancing blow to Earth's magnetic field today. NOAA forecasters estimate a 40% chance of geomagnetic activity if and when the CME arrives. High-latitude sky watchers, be alert for auroras.
COMET AND CME: A comet dove into the sun on May 11th and seemed to trigger a massive eruption--emphasis on seemed. Watch the movie, then scroll down for further discussion.
A comet goes in; a CME comes out. Coincidence? Probably, yes, the sequence was coincidental. The comet disintegrated as much as a million kilometers above the stellar surface. There's no known way that the wispy, vaporous remains of a relatively lightweight comet could cause a billion-ton cloud of hot plasma to fly away from the sun at 400 km/s (the observed speed of the CME). Moreover, NASA's Solar Dynamics Observatory photographed the eruption that did propel the CME into space. There's no comet in the field of view of this must-see movie.
Bonus: The bright comet pictured above had a dim companion. Can you find it?
MORNING PLANETS: The Great Morning Planet Show of May 2011 continued this morning three-way conjunction. "Jupiter, Venus and Mercury formed a compact triangle," reports Mariano Ribas of Argentina. "It was visually stunning in the morning twilight in Buenos Aires."
"When I was taking this picture, suddenly, a giant 'dinosaur' appeared in scene, trying to eat the planets," he adds. "They were a real mouthful."
Four planets are currently dancing around the dawn sky forming new shapes every morning. Look for them at the crack of dawn; and watch out for the dinosaur, too.
more images: from James W. Young of Mt Graham, Arizona; from Elizabeth Warner of Arlington, VA; from Dennis Simmons of Brisbane, Qld , Australia; from Mohammad Mehdi Asgari of Zanjan,Iran; from Geoffrey Wyatt of Sydney Harbour, Australia; from Malcolm Park of Algonquin Park, Ontario; from Alejandro Bergengruen of Pocitos, Montevideo, Uruguay; from Dr. Fritz Helmut Hemmerich of Teide vulcano, Tenerife, Canary Islands; from Simon Chan of Dalkeith, Western Australia
April 2011 Aurora Gallery
[previous Aprils: 2010, 2009, 2008, 2007, 2006, 2005, 2004, 2003, 2002]
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 May 12, 2011 there were 1218 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 |
| ||for out-of-this-world printing and graphics |