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Solar wind
speed: 398.4 km/sec
density: 3.7 protons/cm3
explanation | more data
Updated: Today at 2347 UT
X-ray Solar Flares
6-hr max: C2
2118 UT May18
24-hr: C6
0345 UT May18
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 18 May 13
Sunspot AR1748 has a delta-class magnetic field that harbors energy for X-class solar flares. Credit: SDO/HMI
Sunspot number: 198
What is the sunspot number?
Updated 18 May 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 May 2013

The Radio Sun
10.7 cm flux: 145 sfu
explanation | more data
Updated 18 May 2013

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Planetary K-index
Now: Kp= 3 quiet
24-hr max: Kp= 5
explanation | more data
Interplanetary Mag. Field
Btotal: 8.0 nT
Bz: 5.6 nT south
explanation | more data
Updated: Today at 2347 UT
Coronal Holes: 17 May 13
There are no large coronal holes on the Earthside of the sun. Credit: SDO/AIA.
NOAA Forecasts
Updated at: 2013 May 18 2200 UTC
0-24 hr
24-48 hr
65 %
65 %
40 %
40 %
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 May 18 2200 UTC
0-24 hr
24-48 hr
35 %
30 %
30 %
10 %
20 %
01 %
High latitudes
0-24 hr
24-48 hr
05 %
15 %
20 %
30 %
75 %
40 %
Saturday, May. 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

GEOMAGNETIC STORM: A CME hit Earth's magnetic field on May 18th at around 0100 UT. Although it was just a glancing blow, the impact was enough to spark a G1-class geomagnetic storm. In the United States, Northern Lights descended as far south as Pawnee Buttes, Colorado:

"The aurora was not visible to the naked eye," says photographer Robert Arn. "Only with a 30 second exposure did I know it was there. As I started to collect data, I noticed an electrical storm in the distance. The juxtaposition of the electrical storm and aurora made for a spectacular image. (The moon near the horizon illuminated the landscape.)"

Elsewhere in the United States, faint auroras were sighted or photographed in, e.g., Washington, Vermont, and Iowa. Browse the aurora gallery for more...

Realtime Aurora Photo Gallery

ANOTHER INCOMING CME: As Earth's magnetic field reverberates from one CME strike, a second more potent CME is on the way. It was propelled in our direction by sunspot AR1748, which unleashed an M3-class solar flare on May 17th (0858 UT). Although this is not the strongest flare we've seen from AR1748, it could be the most geoeffective; the sunspot was almost-squarely facing Earth when the blast occurred. NOAA forecasters estimate a 75% chance of polar geomagnetic storms when the cloud arrives. Aurora alerts: text, voice.

The Solar and Heliospheric Observatory took this picture of the CME leaving the sun at 1500 km/s (3.4 million mph) on May 17th:

In the video, the CME appears to hit Mercury, but it does not. It is merely passing in front of the innermost planet. The planet in the line of fire is actually Earth.

Realtime Space Weather Photo Gallery

DISCONNECTION EVENT IN THE TAIL OF COMET LEMMON: Comet Lemmon (C/2012 F6), which is receding from the sun not far beyond the orbit of Earth, has just experienced a "disconnection event." A cloud of dusty plasma is propagating down the comet's tail, shown here in a photo taken by Paul Mortfield on May 15th:

"I was pretty surprised to see this disconnection event when I processed the images," says Mortfield. "The comet is a challenge to photograph because it is so low in the sky at the start of morning twilight."

Disconnection events can be caused by CME impacts. A famous example is that of Comet Encke in 2007. Comet Lemmon, however, is not on the same side of the sun as active sunspot AR1748. It's hard to see how the recent X-flares can be responsible. Nevertheless, solar activity is high, so now is a good time to monitor comet tails. They are very sensitive to stormy space weather.

Comet Lemmon is a pre-dawn object for observers in the northern hemisphere. It is currently gliding alongside the Great Square of Pegasus in the eastern sky before sunrise. The 7th-magnitude comet is too faint to see with the naked eye, but it is visible in medium-to-large backyard telescopes. Observers with computerized GOTO 'scopes should point their optics here.

More about Comet Lemmon: 3D orbit, ephemeris, light curves.

Realtime Comet Photo Gallery

Realtime Aurora 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 May 18, 2013 there were potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Miss Distance
2013 JM22
May 16
7.9 LD
95 m
2013 KA
May 17
2.1 LD
10 m
2013 KB
May 22
3.2 LD
16 m
2004 BV102
May 25
69.9 LD
1.4 km
1998 QE2
May 31
15.2 LD
2.1 km
2009 FE
Jun 4
9.6 LD
230 m
2000 FM10
Jun 5
50.3 LD
1.3 km
2002 KL3
Jun 6
66.4 LD
1.1 km
1999 WC2
Jun 12
39.2 LD
1.9 km
2006 RO36
Jun 18
70.9 LD
1.2 km
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
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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