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CLOSE ENCOUNTER WITH A VW-BUG: Newly-discovered asteroid 2011 CA7 is flying past Earth today only 63,000 miles away, or 1/4th the distance to the Moon. At closest approach around 1930 UT on Feb. 9th, the VW-Bug-sized space rock will zip through the constellation Orion glowing like a 17th magnitude star. [ephemeris] [3D orbit]
SOLAR ACTIVITY HEATS UP: Formerly quiet sunspot 1153 is suddenly crackling with C- and M-class solar flares. NASA Solar Dynamics Observatory recorded this eruption during the waning hours of Feb. 8th:
Movie formats: 1.8 MB iPad, 0.4 MB iPhone, 2 MB mpeg. See also the big still image.
Because sunspot 1153 is rounding the sun's western horizon, these eruptions are not Earth-directed. They are, however, Venus-directed. The second planet from the sun could receive glancing blows from solar plasma clouds in the days ahead. Readers with solar telescopes are encouraged to monitor the action.
HUBBLE FLARE: The Hubble Space Telescope (HST) is famous for many reasons, but visibility isn't one of them. On most nights, the great observatory registers a modest +3 on the magnitude scale, making a disappointingly faint streak as it moves among the stars. But every now and then, Hubble flares:
"I didn't know Hubble could do this," says M. Raşid Tuğral of Antalya, Turkey, who took the picture on Feb. 7th. "The HST suddenly flared to magnitude -2, almost as bright as the planet Jupiter." This is the kind of streak you could see even from brightly-lit cities; in the remote Turkish countryside, "it was dazzling."
Although not widely publicized, Hubble flares have been observed for years by members of the satellite-watching community. The luminous outbursts are caused by sunlight glinting from one of the spacecraft's flat surfaces--possibly the telescope's aperture door or its "aft skirt." Predicting Hubble flares is tricky because they depend sensitively on the telescope's observing schedule. Slewing from one galaxy to another, stopping for calibration, detouring to a newly-reported supernova: any of these actions could produce--or forestall--an absolute shadow-caster.
The only way to see a Hubble flare is to take a chance on looking. Let your cell phone be your guide.
February 2011 Aurora Photo Gallery
[previous Februaries: 2010, 2009, 2008, 2007, 2006, 2004, 2003, 2002]
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 9, 2011 there were 1196 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 |