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Solar wind
speed: 433.2 km/sec
density: 2.5 protons/cm3
explanation | more data
Updated: Today at 2347 UT
X-ray Solar Flares
6-hr max: B5
1750 UT Aug24
24-hr: B7
0930 UT Aug24
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 24 Aug 13
None of these sunspots poses a threat for strong solar flares. Credit: SDO/HMI
Sunspot number: 127
What is the sunspot number?
Updated 24 Aug 2013

Spotless Days
Current Stretch: 0 days
2013 total: 0 days (0%)
2012 total: 0 days (0%)
2011 total: 2 days (<1%)
2010 total: 51 days (14%)
2009 total: 260 days (71%)
Since 2004: 821 days
Typical Solar Min: 486 days

24 Aug 2013

The Radio Sun
10.7 cm flux: 132 sfu
explanation | more data
Updated 24 Aug 2013

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: 5.2 nT
Bz: 0.5 nT north
explanation | more data
Updated: Today at 2347 UT
Coronal Holes: 23 Aug 13
Solar wind flowing from the indicated coronal hole should reach Earth on Aug. 26-27. Credit: SDO/AIA. is now posting daily satellite images of noctilucent clouds (NLCs), which hover over Earth's poles at the edge of space. The data come from NASA's AIM spacecraft. The north polar "daisy" pictured below is a composite of near-realtime images from AIM assembled by researchers at the University of Colorado's Laboratory for Atmospheric and Space Physics (LASP).
Noctilucent Clouds
Switch view: Europe, USA, Asia, Polar
Updated at: 08-24-2013 10:55:02
NOAA Forecasts
Updated at: 2013 Aug 24 2200 UTC
0-24 hr
24-48 hr
05 %
01 %
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: 2013 Aug 24 2200 UTC
0-24 hr
24-48 hr
40 %
20 %
30 %
05 %
10 %
01 %
High latitudes
0-24 hr
24-48 hr
05 %
15 %
20 %
30 %
75 %
30 %
Saturday, Aug. 24, 2013
What's up in space

When is the best time to see auroras? Where is the best place to go? And how do you photograph them? These questions and more are answered in a new book, Northern Lights - a Guide, by Pal Brekke & Fredrik Broms.

Northern Lights - a Guide

WEEKEND GEOMAGNETIC STORMS? NOAA forecasters estimate a 60% to 70% chance of polar geomagnetic storms this weekend. A CME ejected from the sun on Aug. 21 is expected to hit Earth's magnetic field on Aug. 24, with reverberations from the impact continuing through Aug. 25. High-latitude sky watchers should be alert for auroras. Aurora alerts: text, voice.

TWILIGHT AURORAS: It's that time of year. As the midnight sun wanes, auroras are reappearing in Arctic skies. Sky watchers are seeing a mix of colors, twilight-blue + aurora green, that is unique to the end of northern summer:

"This was my first glimpse of Northern Lights this season," says photographer Stian Rekdal, who took the picture on Aug. 23rd from Reine, Nordland, Norway.

More twilight auroras are in the offing. NOAA forecasters estimate a 60% to 75% chance of polar geomagnetic storms this weekend in response to an incoming CME.

Realtime Aurora Photo Gallery

ONE LESS COMET: Subtract one from the Solar System's total count of comets. Yesterday a small unnamed comet dove into the sun and completely evaporated. Click on the image to see the death plunge, animated:

The icy comet, R.I.P., was a member of the Kreutz family. Kreutz sungrazers are fragments from the breakup of a single giant comet many centuries ago. They are seen falling into the sun dozens of times a year. This particular sungrazer measured a few tens of meters in diameter, too small to survive a close approach with the sun.

A much larger sungrazer is on the way. Comet ISON (not a member of the Kreutz family, but a sungrazer nevertheless) will fly through the sun's atmosphere on Thanksgiving Day 2013. Unlike yesterday's tiny comet, Comet ISON is expected to survive its brush with death. The nucleus of ISON is probably wider than 0.5 kilometers, too big to completely evaporate during its transit of the sun's atmosphere. If optimistic estimates are correct, Comet ISON could emerge post-Thanksgiving as one of the brightest comets in many years.

First, however, Comet ISON is paying a visit to Mars on Oct. 1st, giving Mars rovers and satellites a sneak preview of a potentially-Great Comet. Watch this NASA video for details.

Realtime Space Weather Photo Gallery

Realtime Noctilucent Cloud Photo Gallery
[previous years: 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2011]

Realtime Comet Photo Gallery

  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 August 24, 2013 there were 1421 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Miss Distance
1999 CF9
Aug 23
24.7 LD
1.1 km
2013 QR1
Aug 25
8.2 LD
215 m
2002 JR9
Aug 31
63.5 LD
1.4 km
2013 PX6
Sep 21
68.6 LD
1.0 km
2000 DK79
Nov 10
49.1 LD
3.2 km
2011 JY1
Nov 13
8.2 LD
57 m
2001 AV43
Nov 18
2.9 LD
58 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
Space Weather Alerts
  more links...
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