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SUNSET SKY ALERT: When the sun goes down tonight, step outside and look west. Venus, Mars and the 6% crescent Moon have gathered in the twilight for a beautiful three-way conjunction. It's a nice way to end the day: photo gallery.
UNUSUAL COMET DIVE-BOMBS THE SUN: Astronomers are puzzling over a comet that passed "insanely close" to the sun on Feb. 19th. At first glance it appeared to be a small object, not much bigger than a comet-boulder, doomed to disintegrate in the fierce heat. Instead, it has emerged apparently intact and is actually brightening as it recedes from the sun. Click to view a post-flyby movie recorded on Feb. 20th by the Solar and Heliospheric Observatory (SOHO):
Unofficially, the icy visitor is being called "SOHO-2875," because it is SOHO's 2,875th comet discovery.
Karl Battams of the Naval Research Lab explains what's odd about SOHO-2875: "It's a 'non-group comet,' meaning that it does not appear to be related to any other comet or comet family that we have on record."
Most comets that SOHO sees belong to the Kreutz family. Kreutz sungrazers are fragments from the breakup of a single giant comet many centuries ago. They get their name from 19th century German astronomer Heinrich Kreutz, who studied them in detail. SOHO-2875, however, is not one of those fragments.
"Non-group comets like this appear a few times a year, so in that sense it's not too unusual," continues Battams. "But this one is relatively bright. The big question most people will have now is, Can I see it, or will I be able to see it, from Earth? At first I thought the answer was no. But I am very pleasantly surprised--shocked in fact! The comet has brightened dramatically and now is sporting an increasingly impressive tail. Visibility from Earth in a few weeks is no longer out of the question, although I still wouldn't put money on it."
"I'll continue to tweet updates on my twitter.com/SungrazerComets feed, so folks can follow along there too."
Realtime Comet Photo Gallery
(ALMOST NO) CHANCE OF FLARES: Solar activity is very low, and it is likely to remain so for the next 24 hours. All of the sunspots on the solar disk are small and quiet. NOAA forecasters estimate a 1% chance of M- or X-class solar flares on Feb. 20th. Solar flare alerts: text, voice
The face of the sun is mostly blank. For a closer look, click on this image taken by NASA's Solar Dynamics Observatory on Feb. 20th:
There are six sunspot groups, all fading. If their decay continues, a spotless day could be in the offing--the first since July 2014. Stay tuned for quiet
Realtime Space Weather Photo Gallery
Realtime Aurora Photo Gallery
Every night, a network of NASA all-sky cameras scans the skies above the United States for meteoritic fireballs. Automated software maintained by NASA's Meteoroid Environment Office calculates their orbits, velocity, penetration depth in Earth's atmosphere and many other characteristics. Daily results are presented here on Spaceweather.com.
On Feb. 20, 2015, the network reported 5 fireballs.
In this diagram of the inner solar system, all of the fireball orbits intersect at a single point--Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). [Larger image] [movies]
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 February 20, 2015 there were 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 |