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<<back forward>> -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
Solar wind
speed: 434.4 km/sec
density: 5.2 protons/cm3
explanation | more data
Updated: Today at 2344 UT
X-ray Solar Flares
6-hr max: B8
2157 UT Feb11
24-hr: B9
0813 UT Feb11
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 11 Feb 11
Sunspot 1056 is quiet and poses little threat for strong flares. Credit: SDO/HMI
Sunspot number: 38
What is the sunspot number?
Updated 10 Feb 2011

Spotless Days
Current Stretch: 0 days
2011 total: 1 day (3%)
2010 total: 51 days (14%)
2009 total: 260 days (71%)
Since 2004: 820 days
Typical Solar Min: 486 days

Updated 10 Feb 2011

The Radio Sun
10.7 cm flux: 91 sfu
explanation | more data
Updated 10 Feb 2011

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Planetary K-index
Now: Kp= 2 quiet
24-hr max: Kp= 2
explanation | more data
Interplanetary Mag. Field
Btotal: 4.4 nT
Bz: 3.2 nT south
explanation | more data
Updated: Today at 2346 UT
Coronal Holes: 11 Feb 11
Solar wind flowing from the indicated coronal holes should reach Earth between Feb. 13th and 15th. Credit: SDO/AIA.
NOAA Forecasts
Updated at: 2011 Feb 11 2200 UTC
0-24 hr
24-48 hr
05 %
05 %
01 %
01 %
Geomagnetic Storms:
Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm
Updated at: 2011 Feb 11 2200 UTC
0-24 hr
24-48 hr
20 %
20 %
01 %
01 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
20 %
20 %
01 %
01 %
01 %
01 %
Friday, Feb. 11, 2011
What's up in space

Turn your cell phone into a field-tested satellite tracker. Works for Android and iPhone.

Satellite flybys

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 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

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]

  Near Earth Asteroids
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.
Recent & Upcoming Earth-asteroid encounters:
Miss Distance
2011 CF22
Feb 6
0.1 LD
3 m
2011 CA7
Feb 9
0.3 LD
4 m
2011 CZ3
Feb 10
2.5 LD
24 m
2003 YG118
Feb 20
67.7 LD
1.8 km
2000 PN9
Mar 10
45.5 LD
2.6 km
2002 DB4
Apr 15
62.5 LD
2.2 km
2008 UC202
Apr 27
8.9 LD
10 m
2009 UK20
May 2
8.6 LD
23 m
2008 FU6
May 5
75.5 LD
1.2 km
2003 YT1
May 5
65.3 LD
2.5 km
2002 JC
Jun 1
57.5 LD
1.6 km
2009 BD
Jun 2
0.9 LD
9 m
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.
  Essential web links
NOAA Space Weather Prediction Center
  The official U.S. government space weather bureau
Atmospheric Optics
  The first place to look for information about sundogs, pillars, rainbows and related phenomena.
Solar Dynamics Observatory
  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
Solar and Heliospheric Observatory
  Realtime and archival images of the Sun from SOHO.
Daily Sunspot Summaries
  from the NOAA Space Environment Center
  the underlying science of space weather
Science Central
  more links...
©2010 All rights reserved. This site is penned daily by Dr. Tony Phillips.
Spaceweather Flybys

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