Did you miss last night's auroras? Next time get a wake-up call from Spaceweather PHONE.
ASTEROID FLYBY: At 1 o'clock this morning, Universal Time, asteroid 2007 GU1 flew past Earth only 500,000 miles away. There was never any danger of a collision, but the flyby reminds us of another one that ended differently. In 1908, an asteroid about the same size as 2007 GU1 (approximately 50 meters wide) plunged to Earth over Russia's Stony Tunguska River; it exploded in mid-air, leveling 800 sq. miles of Siberian forest. Such an impact occurs every thousand years or so, researchers believe.
COMET LOVEJOY: Last night, Dennis Simmons of Brisbane, Australia, tried to photograph asteroid 2007 GU1 as it zipped past Earth, but finding the space rock too faint, he turned his attention to Comet Lovejoy (C/2007 E2). "I decided to grab some images as a consolation prize," he says. The result is this 2-hour movie:
Photo details: Vixen 102mm refractor, SBIG ST7E CCD camera, 50 x 2 minutes
"Watching the fuzzy nucleus glide so eerily, effortlessly and silently past the fixed pattern of stars was quite mesmerizing, " he says. "Soon, two hours had been swallowed up by the night as dawn rushed in with birdsong and twilight bursting all around."
Comet Lovejoy is too faint to see with the unaided eye, but at 8th magnitude it is an easy target for backyard telescopes. Look for it in the constellation Aquila before dawn--just to the left of Jupiter. [sky map] [ephemeris]
PROMINENCE ALERT: Got a solar telescope? Point it at the sun. There's a beautiful prominence dancing over the northwestern limb, shown here in a 2-day movie from the Solar and Heliospheric Observatory (SOHO):
Solar activity, April 14-16, 2007. Credit: SOHO Extreme UV Telescope
Although the prominence looks like a flickering flame, it is not fire. Prominences are clouds of hydrogen held above the sun's surface by magnetic force fields. There's no combustion involved, as happens at the tip of a match. These clouds glow simply because they are hot--you would be too if you were so close to the surface of the sun!