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Solar wind
speed: 513.5 km/sec
density: 4.7 protons/cm3
explanation | more data
Updated: Today at 2347 UT
X-ray Solar Flares
6-hr max: C2
2017 UT Jul18
24-hr: C2
2017 UT Jul18
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 18 July 13
Sunspot AR1793 has a beta-gamma-delta magnetic field that harbors energy for M-class solar flares. Credit: SDO/HMI
Sunspot number: 74
What is the sunspot number?
Updated 18 Jul 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 Jul 2013

The Radio Sun
10.7 cm flux: 111 sfu
explanation | more data
Updated 18 Jul 2013

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Planetary K-index
Now: Kp= 4 unsettled
24-hr max: Kp= 4
explanation | more data
Interplanetary Mag. Field
Btotal: 8.6 nT
Bz: 0.3 nT north
explanation | more data
Updated: Today at 2346 UT
Coronal Holes: 18 Jul 13
Solar wind flowing from the indicated coronal hole could reach Earth on July 19-21. 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: 07-18-2013 10:55:02
NOAA Forecasts
Updated at: 2013 Jul 18 2200 UTC
0-24 hr
24-48 hr
15 %
15 %
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 Jul 18 2200 UTC
0-24 hr
24-48 hr
45 %
45 %
20 %
20 %
05 %
05 %
High latitudes
0-24 hr
24-48 hr
10 %
10 %
25 %
25 %
65 %
65 %
Thursday, Jul. 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

THE FIRST INTERPLANETARY PHOTOBOMB: On Friday, July 19th, the Cassini spacecraft will photograph Earth through the rings of Saturn--and NASA wants you to jump into the shot. Get the full story from Science@NASA.

CORONAL HOLE: Opening up like a zipper almost a million kilometers long, a vast coronal hole has appeared in the sun's northern hemisphere. NASA's Solar Dynamics Observatory took this picture of the UV-dark chasm on July 18th:

Coronal holes are places in the sun's upper atmosphere where the magnetic field opens up and allows solar wind to escape. A broad stream of solar wind flowing from this particular coronal hole should reach Earth on July 19-20.

In addition, NOAA forecasters say a CME could hit Earth's magnetic field late on July 18th. The combined impact of the CME and the incoming solar wind stream could cause some stormy space weather around Earth in the days ahead. NOAA forecasters estimate a 50% - 65% chance of polar geomagnetic storms on July 18-20. Aurora alerts: text, voice.

Realtime Aurora Photo Gallery

HOW HIGH ARE NOCTILUCENT CLOUDS? Noctilucent clouds are our planet's highest clouds--but exactly how high are they? The textbook answer is 82-82 km, but textbooks can be wrong. Peter Rosén of Stockholm, Sweden, decided to find out for himself. "On July 4th I photographed some interesting NLCs," he explains. "After uploading them on Spaceweather, I noticed that P-M Hedén had photographed the same formations and at the same time from a location 26 km (16 miles) north of mine. I decided to make precise measurements of the same features in both pictures with respect to the stars and try to determine the exact geographical position and height of these NLCs." Scroll past the images to learn more:

"Some years ago I found a very useful calculator put online by Paul Schlyter to measure the position and altitude of Perseid meteors. By entering the geographical position of both observers and the respective coordinates of an object in the sky, it will compute the position and altitude of the object. In this case, I used it for NLCs."

He picked four features color-coded in the figure above (best seen in the full-sized version) and measured their positions. "The height of these NLCs ranged from 75.1 km (blue dot) to 78.6 km (red dot)," he says. "These results seem to be a little bit lower than the value of 83 km that is often referenced."

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

Realtime Space Weather Photo Gallery

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 July 18, 2013 there were 1397 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Miss Distance
2001 PJ9
Jul 17
29.2 LD
1.1 km
2006 BL8
Jul 26
9.3 LD
48 m
2003 DZ15
Jul 29
7.6 LD
153 m
2005 WK4
Aug 9
8.1 LD
420 m
1999 CF9
Aug 23
24.7 LD
1.1 km
2002 JR9
Aug 31
63.5 LD
1.4 km
1992 SL
Sep 23
70 LD
1.1 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.
  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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