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<<back forward>> -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
Solar wind
speed: 402.7 km/sec
density: 1.9 protons/cm3
explanation | more data
Updated: Today at 2343 UT
X-ray Solar Flares
6-hr max: C1
2227 UT Sep18
24-hr: C3
1057 UT Sep18
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 18 Sep 11
Sunspot 1295 poses a threat for Earth-directed C-flares. Credit: SDO/HMI
Sunspot number: 138
What is the sunspot number?
Updated 17 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 17 Sep 2011

The Radio Sun
10.7 cm flux: 145 sfu
explanation | more data
Updated 17 Sep 2011

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Planetary K-index
Now: Kp= 1 quiet
24-hr max: Kp= 2
explanation | more data
Interplanetary Mag. Field
Btotal: 5.2 nT
Bz: 1.6 nT north
explanation | more data
Updated: Today at 2346 UT
Coronal Holes: 18 Sep 11
There are no large coronal holes on the Earth-facing side of the sun. Credit: SDO/AIA.
NOAA Forecasts
Updated at: 2011 Sep 18 2200 UTC
0-24 hr
24-48 hr
35 %
35 %
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 Sep 18 2200 UTC
0-24 hr
24-48 hr
10 %
05 %
01 %
01 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
10 %
05 %
01 %
01 %
01 %
01 %
Sunday, Sep. 18, 2011
What's up in space

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

Satellite flybys

REENTRY ALERT: NASA reports that UARS, an atmospheric research satllite the size of a small bus, will re-enter Earth's atmosphere on Sept. 23, plus or minus one day. Not all of the spectacularly-disintegrating spacecraft will burn up in the atmosphere; debris could be scattered along a ground track some 500 miles long. Because of the rapid evolution of UARS's decaying orbit, the location of the debris zone is not yet known. A NASA risk assessment places the odds of a human casualty at 1:3200. For last-chance sightings of UARS, check the Simple Satellite Tracker or download the Satellite Flybys app for your smartphone.

SUBSIDING STORM: A coronal mass ejection (CME) hit Earth's magnetic field on Sept 17th, sparking a moderate geomagnetic storm and auroras around the Arctic Circle. The view from Siberia was exquisite:

"I took the picture using my Nikon D3 digital camera," says photographer Ruslan Ahmetsafin of Aykhal, Siberia. "The sky was full of green."

The storm is subsiding now. Nevertheless, high-latitude sky watchers should remain alert for auroras as Earth's magnetic field continues to reverberate from the CME's impact. Aurora alerts: text, voice.

more images: from Michael Kunze flying 30,000 ft over Greenland; from Chad Blakley of Abisko National Park, Sweden; from Joseph Bradley of Whitehorse, Yukon; from B.Art Braafhart of Salla, Finnish-Lapland; from Laffen Jensen of Stjorda, Trondheim, Norway; from John Dean of Dexter, Alaska

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

GOODBYE SUNSPOT 1289: This weekend, big sunspot AR1289 is approaching the sun's western limb where it will soon disappear from view. Jesús Carmona de Argila of Madrid, Spain, captured these parting shots on Sept. 17th:

The image on the left was taken through an "H-alpha" filter tuned to the red glow of solar hydrogen. It reveals a long magnetic filament trailing the sunspot's dark core. This structure has prompted some observers to nickname AR1289 "the tadpole." The image on the right was taken through a white light filter. It shows the sunspot as the human eye would see it if the sun weren't so blindingly bright. The departing sunspot, while photogenic, poses little threat for Earth-directed flares.

more images: from Jo Dahlmans of Ulestraten The Netherlands; from Gianluca Valentini of Rimini, Italy; from John Chumack of Dayton, Ohio; from Francois Rouviere of Mougins, France; from James Kevin Ty of Manila , Philippines

  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 18, 2011 there were 1244 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Miss Distance
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
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
2000 YA
Dec 26
2.9 LD
80 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
Conquest Graphics
  for out-of-this-world printing and graphics
Trade Show Displays
  more links...
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