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. | | |
CRESCENT MOON: Tonight, the crescent Moon is passing almost directly between Mars and Saturn. A good view of the western horizon is required to see the crossing. If you have one, go outside just after sunnset and take a look. Sky maps: Sept. 18, 19. Images: #1.
INCOMING ACTIVE REGIONS: Solar activity has been low for more than a week. This could change in the days ahead as a pair of active regions rotates onto the Earthside of the sun. NASA's Solar Dynamics Observatory recorded the signs of their approach during the early hours of Sept. 18th:
Pictured above are the magnetic canopies of sunspots. Plasma-filled magnetic loops towering more than 50,000 km above the sun's eastern limb herald the approach of the active regions, possibly turning a pair of flare centers toward Earth as the week unfolds. Amateur astronomers witth backyard solar telescopes should train their optics on the eastern limb; solar activity is in the offing. Solar flare alerts: text, voice.
AUTUMN LIGHTS: Northern autumn is only days away, and that means aurora season is underway. For reasons researchers don't fully understand, equinoxes are the best times to see Northern Lights. The show is well underway at Summit Station, an NSF-sponsored research facility on top of the Greenland ice sheet, where Ed Stockard snapped this photo last night:
"The auroras came on fast and furious, moving and dancing across the entire sky," says Stockard. "Aurora season has definitely begun on top of the ice sheet. Bring on the lights! Tonight's temperature was - 35F with five knots of wind.... time to dress for the space weather."
NOAA forecasters estimate a 25% to 30% chance of strong polar geomagnetic storms for the next three nights as a series of solar wind streams gently buffet Earth's magnetic field. High latitude sky watchers should remain alert for auroras. Aurora alerts: text, voice.
Realtime Aurora Photo Gallery
Realtime Space Weather 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 September 18, 2012 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 |