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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SEE THE SECRET SPACE PLANE: Readers in the USA and Canada, for the next week or so, the US Air Force's "secret" X-37B space plane will be making visible passes over many North American towns and cities. Check the Simple Satellite Tracker for viewing times--or turn your cell phone into a space plane tracker. It's simple.
EARTH DODGES ANOTHER BULLET: Just as sunspot 1105 was turning away from Earth on Sept. 8th, the active region erupted, producing a C3-class solar flare (peak @ 2330 UT) and a fantastic prominence. Here is a snapshot from the Solar Dynamics Observatory:
The eruption also hurled a bright coronal mass ejection (CME) into space: SOHO movie. The expanding cloud is heading into a part of the solar system not currently occupied by any planet--it's going to miss everything, including Earth. If such a CME did hit Earth's magnetic field, it would probably trigger strong geomagnetic storms. Maybe next time...
Update #1: Two new movies of the eruption are available from the Solar Dynamics Observatory--a big picture view in black-and-white and a spectacular close-up in three extreme ultraviolet colors.
Update #2: NASA's STEREO-Ahead spacecraft is stationed almost directly above sunspot 1105. A first-look movie shows a shadowy "solar tsunami" wave racing away from the blast site.
PURPLE AURORAS: Auroras are dancing around the Arctic Circle and some of them are purple. This is how the sky looked on Sept. 8th over Bø, Norway:
"It's not often I get to see purple auroras," says photographer Øystein Lunde Ingvaldsen. "This was truly a fantastic sight!"
Auroras get their colors from specific atoms and molecules in Earth's atmosphere. Green comes from oxygen molecules excited by geomagnetic activity. Purple, on the other hand, is usually a mixture of red and blue emissions from molecular nitrogen. O2 and N2 were both revved up in Norway last night!
More purple is possible tonight as a solar wind stream continues to buffet Earth's magnetic field. High-latitude sky watchers should remain alert for auroras.
NEW: 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 9, 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 |