iPHONE VS ANDROID! Actually, it doesn't matter which phone you carry. Our cool, new app turns both smartphones into field-tested satellite trackers. Learn more.
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THIS PLANET SMELLS FUNNY: An alien world in the constellation Leo is breaking the rules of giant-planet chemistry, prompting researchers to re-think the make-up of exoplanet atmospheres. Get the full story from Science@NASA.
SPACE STATION RADAR ECHO: The US Air Force Space Surveillance Radar in Kickapoo, Texas, is constantly scanning the heavens for objects orbiting or passing by Earth. Yesterday, it caught a whopper. At 21:13 CDT on Sept. 13th, the International Space Station passed through the radar beam, producing a powerful echo. Click on the image to listen:
The sound you just heard came from the loudspeaker of a receiver in Roswell, New Mexico, where radio engineer Stan Nelson recorded event. "The ISS was passing over Lubbock, Texas--midway between me and the Air Force radar," says Nelson. "It was the perfect geometry for catching the echo."
As the ISS raced through the radar beam, its velocity vector rotated with respect to the transmitter below. That's why the echo sounds like the frequency-shifting whistle of a passing train. It's the Doppler effect, working in space the same way it does on Earth.
The space station will be making more passes through the radar beam in the days ahead: Sep. 15 @ 20:31:37 CDT; Sep. 17 @ 11:48:29 CDT; Sep. 19 @ 11:06:38 CDT. Tune in to SpaceWeather Radio for live echoes.
AURORA WATCH: There's a reason they call Alaska "aurora country." Last night near Fairbanks, for no particular reason, the sky turned green:
"It was a nice quiet display that lasted more than an hour," reports photographer Lance Parrish of Skiland. "I had plenty of time to record the show using my Nikon D3. A 10 second exposure at 1600 ISO worked very nicely."
Alaskans and other Northerners should take note of those settings, because tonight there is a reason for auroras. The sun's magnetic field is tipping south, opening a crack in Earth's magnetosphere. Solar wind pouring in could fuel a renewed display.
Sept. 2010 Northern Lights Gallery
[previous Septembers: 2009, 2008, 2007, 2006, 2005, 2004, 2002, 2001, 2000]
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 14, 2010 there were 1144 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 |
| ||from the National Solar Data Analysis Center |