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FULL WOLF MOON: There's a full Moon tonight and according to folklore it has a special name: the Full Wolf Moon. Arcing high through the winter sky, the bright orb turns night into a simulacrum of day and shines through freezing clouds, producing spectacular ice halos. Go outside, take a look, and try not to howl.
A HOLE IN THE SUN'S ATMOSPHERE: A vast hole has opened in the atmosphere over the sun's south pole, and it is spewing solar wind into space. The gaseous gap, a.k.a. a 'coronal hole,' is colored dark-purple in this extreme ultraviolet image from NASA's Solar Dynamics Observatory:
Curved lines trace the sun's magnetic field in this EUV image from SDO
Coronal holes are places where the sun's magnetic field opens up and allows solar wind to escape. A stream of solar wind flowing from this particular hole is expected to reach Earth's orbit on Jan. 4-5. The bulk of the stream will flow south of our planet. However, not all of it will miss. NOAA forecasters estimate a 40% chance of polar geomagnetic storms when the solar wind arrives in the next 48 hours. Aurora alerts: text, voice
Realtime Aurora Photo Gallery
VENUS AND MERCURY: Tonight, when the sun goes down, step outside and face west. Mercury and Venus are converging in the sunset sky. Japanese photographer "Shiraishi" sends this picture from Kumagaya-shi, Saitama:
"Venus popped out of the twilight first, then Mercury followed as the sky darkened," says Shiraishi. "To capture the pair I used a Nikon COOLPIX P510 digital camera set at ISO 400 for a 1/6s exposure."
Sunset photographers should take note of those settings, because the Mercury-Venus show is just beginning. For the next week, the two planets will draw closer and closer together. On the date of closest approach, Jan. 10th, they will be a scant 0.7 degrees apart--three times closer than they are tonight! The width of your little finger held at arm's length is enough to eclipse the pair.
If you can't see Mercury with the naked eye alone, you might be looking too soon after sunset. Wait a while for the twilight to deepen. Or if you have binoculars, aim them at Venus to reel in Mercury. Once you find Mercury, you might be surprised at how bright it appears.
Monitor Spaceweather.com's photo gallery for Venus-Mercury snapshots from around the world. Better yet, go outside and see for yourself.
Realtime Space Weather Photo Gallery
Realtime Comet 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 Jan. 4, 2015, the network reported 51 fireballs.
(42 sporadics, 6 Quadrantids, 1 January Leonid, 1 December Leonis Minorid, 1 alpha Hydrid)
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 January 4, 2015 there were 1531 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 |