Turn your cell phone into a field-tested satellite tracker. Works for Android and iPhone.
| || |
SDO SUNDOG MYSTERY: One year ago, NASA's Solar Dynamics Observatory amazed observers when it destroyed a sundog en route to orbit. A new analysis of the event is shedding light on the surprising way rocket shock-waves interact with clouds. Get the full story from Science@NASA.
PHOTOGRAPH THE SOLAR SAIL, WIN MONEY: NASA and Spaceweather.com have joined forces to launch a photo contest. Photographers who catch NanoSail-D in the act of flaring could win as much as $500. Check the Simple Satellite Tracker (web or cell phone) to see if you are favored with a flyby in the nights ahead. Contest details may be found at nanosail.org.
SOLAR TSUNAMI: Imagine a wave of hot plasma towering higher than Earth itself, rippling out from a central point in a circular pattern millions of kilometers in circumference. Researchers recently realized that such monster waves are real, and they happen routinely on the sun. Just yesterday, one of them surged over the western limb. Click on the image to view the shadowy yet staggering solar tsunami of Feb. 10th:
Movie credit: NASA's Solar Dynamics Observatory
The source of the wave was active sunspot 1153, currently located on the far side of the sun. An eruption in the sunspot's magnetic canopy propelled a shock wave across the stellar surface--all the way over the horizon where it could be seen from Earth. Sequences like this show how farside sunspots can actually "reach around" to affect the Earth-side of the sun. Suppose that wave ran into a magnetic filament , destabilized it, and triggered an explosion aimed at our planet. It's happened before. Imagine that.
TEXAS SUNDOG: If there's snow on the ground and ice in the air, it must be ... Texas? The historic winter storms of 2011 have frozen some unaccustomed places, hence the following photo from Amarillo:
"This very bright sundog appeared on the morning of Feb 9th--very rare in our part of the world," says photographer David Blackburn.
Sundogs are formed by ice crystals in the air. Hexagonal plate-shaped crystals flutter down from the sky like leaves falling from trees. Aerodynamic forces align their flat sides parallel to the ground, and when sunlight hits a patch of well-aligned crystals at the right distance from the sun, voila!--a sundog. Look for sundogs around sunrise and sunset when the low-hanging sun is well positioned to shine through the fluttering ice. Yes, even in Texas.
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 11, 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 |