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Solar wind
speed: 559.6 km/sec
density: 2.2 protons/cm3
explanation | more data
Updated: Today at 2347 UT
X-ray Solar Flares
6-hr max: B5
1830 UT Sep18
24-hr: C3
0315 UT Sep18
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 18 Sep 13
The Earthside of the sun is very quiet. Solar activity remains low. Credit: SDO/HMI
Sunspot number: 80
What is the sunspot number?
Updated 18 Sep 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

18 Sep 2013

The Radio Sun
10.7 cm flux: 99 sfu
explanation | more data
Updated 18 Sep 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: 4.2 nT
Bz: 1.5 nT south
explanation | more data
Updated: Today at 2347 UT
Coronal Holes: 18 Sep 13
Solar wind flowing from this coronal hole could reach Earth on Sept. 22-23. 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: 09-02-2013 11:55:02
NOAA Forecasts
Updated at: 2013 Sep 18 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: 2013 Sep 18 2200 UTC
0-24 hr
24-48 hr
10 %
10 %
01 %
01 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
15 %
15 %
25 %
25 %
10 %
10 %
Wednesday, Sep. 18, 2013
What's up in space

They came from outer space--and you can have one! Genuine meteorites are now on sale in the Space Weather Store.

Own your own meteorite

HARVEST MOON TONIGHT: Tonight's full Moon is the "Harvest Moon," the full Moon closest to the autumnal equinox. Look for it rising in the east at sunset. Swollen by the Moon illusion and reddened by the effect of low-hanging clouds, the rising Harvest moon is often likened to a "Great Pumpkin." Get the full story and a video from Science@NASA.

AWAKENING SUN: After a week of deep quiet, the drowsy sun is waking up. Five new sunspots were numbered on Sept. 17th as the sun hurled a series of CMEs (movie) into space, none Earth directed. One of the new sunspots, AR1486, is crackling with C-class solar flares. NASA's Solar Dynamics Observatory recorded this C3-flare during the early hours of Sept.18th:

So far, the flares coming from AR1846 are relatively minor C-class events. The active region might be capable of more potent flares. We don't know yet, though, because the foreshortening of AR1846 near the sun's limb prevents a full evaluation of its magnetic field, where the energy for flares is stored. Stay tuned for updates. Solar flare alerts: text, voice.

Realtime Space Weather Photo Gallery

COMET ISON: Comet ISON is still more than two months away from its spectacular close encounter with the sun. Amateur astronomers aren't waiting. The brightening comet has become a good target for backyard telescopes in the pre-dawn sky and pictures of the comet are pouring in. Last night, Chris Schur captured this image from his home observatory in Payson, Arizona:

"This 25 minute exposure shows the comet through a 12 inch telescope," says Schur. "The image has sharp focus, perfect tracking and the star trails are unbroken and smooth. A nearby star added to the nice composition."

At the moment, ISON is too dim for the naked eye--"I estimate the comet's magnitude to be +12.5," says Schur--but it is on track to become an impressive sungrazer. For comparison, Comet ISON is brighter than Comet Lovejoy was in 2011 at a similar distance from the sun. The fact that Comet Lovejoy turned into a spectacular sungrazer bodes well for the performance of Comet ISON.

Observers of Comet ISON will notice that it is in the same part of the sky as Mars. The comet will make a close approach to the Red Planet on October 1st, and during that time Mars satellites will be taking ISON's picture at point blank range. Those images will likely rival or improve upon the view from Earth. Stay tuned to the Comet ISON Photo Gallery for updates from both planets.

Realtime Comet ISON Photo Gallery

Realtime Aurora 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 September 18, 2013 there were potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Miss Distance
2013 RT73
Sep 16
8.3 LD
49 m
2013 RM73
Sep 17
2.3 LD
20 m
2013 RF74
Sep 18
5.5 LD
25 m
2013 RZ53
Sep 18
0.6 LD
3 m
2000 DK79
Nov 10
49.1 LD
3.2 km
2011 JY1
Nov 13
8.2 LD
57 m
2001 AV43
Nov 18
3 LD
57 m
2010 CL19
Nov 25
37.6 LD
1.3 km
2013 NJ
Nov 26
2.5 LD
180 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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