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Solar wind
speed: 471.8 km/sec
density: 1.2 protons/cm3
explanation | more data
Updated: Today at 2347 UT
X-ray Solar Flares
6-hr max: C1
1932 UT Mar20
24-hr: C5
0103 UT Mar20
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 20 Mar 13
Solar activity is low. None of these sunspots poses a threat for strong flares. Credit: SDO/HMI
Sunspot number: 68
What is the sunspot number?
Updated 20 Mar 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

20 Mar 2013

The Radio Sun
10.7 cm flux: 110 sfu
explanation | more data
Updated 20 Mar 2013

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Planetary K-index
Now: Kp= 3 quiet
24-hr max: Kp= 3
explanation | more data
Interplanetary Mag. Field
Btotal: 6.8 nT
Bz: 3.6 nT south
explanation | more data
Updated: Today at 2347 UT
Coronal Holes: 20 Mar 13
Solar wind flowing from this coronal hole could reach Earth on March 20-21. Credit: SDO/AIA.
NOAA Forecasts
Updated at: 2013 Mar 20 2200 UTC
0-24 hr
24-48 hr
15 %
10 %
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 Mar 20 2200 UTC
0-24 hr
24-48 hr
20 %
15 %
05 %
05 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
20 %
15 %
35 %
20 %
30 %
20 %
Wednesday, Mar. 20, 2013
What's up in space

Hang the Transit of Venus on your wall! Hubble-quality images from NASA's Solar Dynamics Observatory are now available as metallic posters in the Space Weather Store.

Venus Transit metal posters

ADVERTISE AT THE EDGE OF SPACE: is pleased to announce a unique advertising opportunity. We can launch your ad banner or product to the edge of space itself. Take a look at this running shoe or this bobble-head figure. In collaboration with Earth to Sky Calculus, a student-run corporation based in Bishop, California, will fly a helium research balloon to 120,000 feet where your ad, picture, birthday greeting or other item can be photographed against the limb of the Earth. Liftoff is scheduled for 9 am on April 22nd, Earth Day 2013! Contact Dr. Tony Phillips for pricing and details.

AURORAS LOVE EQUINOXES: The seasons are changing. Today, March 20th, the sun is crossing cross the celestial equator heading north. This marks the beginning of spring in the northern hemisphere and autumn in the southern hemisphere. At this time of year, day and night are of nearly equal length, hence the name "equinox" (equal night).

For reasons researchers don't fully understand, auroras love equinoxes. During the weeks around the beginning of spring or fall, the slightest gust of solar wind can provoke bright lights around the poles. A potent CME impact at this time can produce an unforgettable display, like this one only a few days ago:

"I took this photo during the historic St. Patrick's Day geomagnetic storm of 2013," says Ben Hattenbach of Fairbanks, Alaska. "I'm still exhausted from the experience, during which the aurora was at or near peak strength for the entire night. It was just incredible in a way pictures cannot come close to conveying."

With the beginning of northern spring, the stage is set for more auroras tonight. NOAA forecasters estimate a 20% - 30% chance of polar geomagnetic storms on March 20-21. Aurora alerts: text, voice.

Realtime Aurora Photo Gallery

COMET DODGES CMEs: NASA's STEREO-B spacecraft has been monitoring Comet Pan-STARRS, taking hundreds of pictures as the comet passed by the sun this month. Yesterday, analyst Karl Battams of the Naval Research Lab assembled the data into a single movie spanning eight days, from March 9th through 16th. Click to set the scene in motion:

STEREO-B is stationed over the farside of the sun, so cameras onboard the spacecraft can look back and see Earth as well as the comet. In Battams' movie, the sun is located just outside the field of view on the left. Massive clouds of magnetized plasma (CMEs) billow away from the sun toward the comet, but according to Battams, none hit their mark:

"There were two CMEs in that sequence and it seems they went either side of the comet," he says. "That's a shame for us scientists because we would like to study how CMEs interact with a comet."

CMEs have been known to rip the tails off comets that pass too close to the sun, but that did not happen to Comet Pan-STARRS.

"By the way," adds Battams, "I've looked closely at the STEREO images and can see no indication of the possible fragment recently reported on I also haven't noticed any unusual brightening or disruption in the comet tail that would hint at such a fragmentation event having occurred."

More: NASA video, 3D orbit, ephemeris, light curves.

Realtime Comet Photo Gallery

Realtime Space Weather Photo Gallery

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

  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 March 20, 2013 there were potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Miss Distance
2013 EA29
Mar 14
3.5 LD
20 m
2013 ED68
Mar 16
1.4 LD
11 m
2007 EO88
Mar 18
4.4 LD
23 m
1993 UC
Mar 20
49 LD
3.8 km
2013 ES11
Mar 22
6.3 LD
80 m
2013 FG
Mar 24
3.8 LD
33 m
2013 FD8
Mar 27
8.4 LD
28 m
1997 AP10
Mar 28
45.9 LD
1.8 km
2013 EL89
Mar 29
4.6 LD
30 m
2013 FB8
Mar 30
4.2 LD
44 m
2010 GM23
Apr 13
3.9 LD
50 m
2005 NZ6
Apr 29
24.9 LD
1.3 km
2001 DQ8
Apr 30
74.3 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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