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SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
 
Solar wind
speed: 384.5 km/sec
density: 0.5 protons/cm3
explanation | more data
Updated: Today at 2343 UT
X-ray Solar Flares
6-hr max: C2
2108 UT Sep21
24-hr: M1
1223 UT Sep21
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 21 Sep 11
Sunspots 1301 and 1295 are crackling with C-flares. Credit: SDO/HMI
Sunspot number: 101
What is the sunspot number?
Updated 20 Sep 2011

Spotless Days
Current Stretch: 0 days
2011 total: 2 days (<1%)
2010 total: 51 days (14%)
2009 total: 260 days (71%)
Since 2004: 821 days
Typical Solar Min: 486 days

Updated 20 Sep 2011


The Radio Sun
10.7 cm flux: 144 sfu
explanation | more data
Updated 20 Sep 2011

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/POES
Planetary K-index
Now: Kp= 2 quiet
24-hr max: Kp= 2
quiet
explanation | more data
Interplanetary Mag. Field
Btotal: 6.2 nT
Bz: 2.5 nT north
explanation | more data
Updated: Today at 2346 UT
Coronal Holes: 21 Sep 11
There are no large coronal holes on the Earth-facing side of the sun. Credit: SDO/AIA.
SPACE WEATHER
NOAA Forecasts
Updated at: 2011 Sep 21 2200 UTC
FLARE
0-24 hr
24-48 hr
CLASS M
45 %
45 %
CLASS X
10 %
10 %
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 Sep 21 2200 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
05 %
05 %
MINOR
01 %
01 %
SEVERE
01 %
01 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
10 %
10 %
MINOR
01 %
01 %
SEVERE
01 %
01 %
 
Wednesday, Sep. 21, 2011
What's up in space
 

Are we alone? Your iPhone has the answer. Download the all-new Drake Equation app to calculate the population of the Milky Way.

 
DrakeEQ for iPhone and iPad

RE-ENTRY ALERT: UARS, a NASA satellite the size of a small bus, will re-enter the atmosphere later this week. Best estimates place the re-entry time during the late hours of Sept. 23rd over a still-unknown region of Earth. "It is still too early to predict the time and location of re-entry," says NASA. "Predictions will become more refined over the next two days."

The disintegration of UARS is expected to produce a fireball that could be visible even in broad daylight. Not all of the spacecraft will burn up in the atmosphere, however; according to a NASA risk assessment, as many as 26 potentially hazardous pieces of debris could be scattered along a ground track some 500 miles long. The same report puts the odds of a human casualty at 1 in 3200.

On Sept. 15th, astrophotographer Theirry Legault video-recorded the doomed satellite during one of its last passes over France:


Photo details: Celestron 14" EdgeHD, Takahashi EM400 mount modified for fast tracking. Range to UARS: 252 km.

"The satellite appears to be tumbling, perhaps because a collision with satellite debris a few years ago," notes Legault. "The variations in brightness are rapid and easily visible to the human eye." (Other observers have reported UARS flashes almost as bright as Venus.)

For last-chance sightings of this brightly flashing satellite, please check the Simple Satellite Tracker or download the Satellite Flybys app for your smartphone.

more images: from Oscar Martín Mesonero of Madrid, Spain

AURORA WATCH: "Last night was magical here in Inari, Finland," reports Andy Keen. "The moonlight, clouds and stars framed a beautiful display of aurora borealis." He photographed the scene just after midnight:

More midnight magic could be in the offing. A coronal mass ejection (CME) is heading toward Earth and it could deliver a glancing blow to our planet's magnetic field on Sept. 22th around 23:00 UT. High-latitude sky watchers should be alert for auroras when the CME arrives. Aurora alerts: text, voice.

more images: from Andrew Hindley of Inari, finland

September 2011 Aurora Gallery
[previous Septembers: 2010, 2009, 2008, 2007, 2006, 2005, 2004]

  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 September 21, 2011 there were 1244 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Mag.
Size
2003 QC10
Sep 18
50 LD
--
1.2 km
2004 SV55
Sep 19
67.5 LD
--
1.2 km
2007 TD
Sep 22
6.2 LD
--
58 m
2011 SO5
Sep 29
5.6 LD
--
35 m
2002 AG29
Oct 9
77.1 LD
--
1.0 km
2000 OJ8
Oct 13
49.8 LD
--
2.4 km
2009 TM8
Oct 17
0.9 LD
--
8 m
2011 FZ2
Nov 7
75.9 LD
--
1.6 km
2005 YU55
Nov 8
0.8 LD
--
175 m
1994 CK1
Nov 16
68.8 LD
--
1.5 km
1996 FG3
Nov 23
39.5 LD
--
1.1 km
2003 WM7
Dec 9
47.6 LD
--
1.5 km
1999 XP35
Dec 20
77.5 LD
--
1.0 km
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.
STEREO
  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
Heliophysics
  the underlying science of space weather
Science Central
 
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Trade Show Displays
   
  more links...
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