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Solar wind
speed: 374.5 km/sec
density: 2.9 protons/cm3
explanation | more data
Updated: Today at 2347 UT
X-ray Solar Flares
6-hr max: M1
2154 UT May16
24-hr: M1
2154 UT May16
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 16 May 13
Sunspot AR1748 has a dela-class magnetic field that harbors energy for X-class solar flares. Credit: SDO/HMI
Sunspot number: 186
What is the sunspot number?
Updated 16 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

16 May 2013

The Radio Sun
10.7 cm flux: 146 sfu
explanation | more data
Updated 16 May 2013

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Planetary K-index
Now: Kp= 2 quiet
24-hr max: Kp= 4
explanation | more data
Interplanetary Mag. Field
Btotal: 5.0 nT
Bz: 0.8 nT north
explanation | more data
Updated: Today at 2347 UT
Coronal Holes: 16 May 13
There are no large coronal holes on the Earthside of the sun. Credit: SDO/AIA.
NOAA Forecasts
Updated at: 2013 May 16 2200 UTC
0-24 hr
24-48 hr
75 %
75 %
50 %
50 %
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 16 2200 UTC
0-24 hr
24-48 hr
30 %
15 %
10 %
05 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
15 %
15 %
30 %
25 %
40 %
25 %
Thursday, May. 16, 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

POSSIBLE CME IMPACT ON MAY 17: A coronal mass ejection (CME) hurled into space by the X1-flare of May 15th might deliver a glancing blow to Earth's magnetic field on May 17th. NOAA forecasters estimate a 40% chance of polar geomagnetic storms when the cloud arrives. High-latitude sky watchers should be alert for auroras. Aurora alerts: text, voice.

X-FLARE THREAT CONTINUES: Sunspot AR1748 has already unleashed four X-class solar flares, but it might not be finished. The active region continues to grow beneath a delta-class magnetic field that harbors energy for powerful eruptions. NOAA puts the odds of another X-flare today at 60%. Solar flare alerts: text, voice.

NASA's Solar Dynamics Observatory took this picture of AR1748 during the early hours of May 16th:

The sunspot is not particularly large, but it is complex, with many dark cores scattered through its zone of influence. This is a sign of a complicated overlying magnetic field. Magnetic complexity is the source of AR1748's explosiveness: when tangled lines of magnetic force cross and reconnect--bang! A flare occurs.

All by itself, AR1748 has produced more X-flares than every other sunspot of the past year combined. In summary, AR1748 has given us an X1.7-class flare (0217 UT on May 13), an X2.8-class flare (1609 UT on May 13), an X3.2-class flare (0117 UT on May 14), and an X1-class flare (0152 on May 15). More could be in the offing. Solar flare alerts: text, voice.

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 amateur astronomer 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

ION WAVES IN THE ATMOSPHERE: Although AR1748 is not directly facing Earth, its strong flares have nevertheless affected our atmosphere. UV and X-radiation hitting the top of the atmosphere ionizes atoms and molecules, creating ion waves over the dayside of the planet. Roberto Battaiola detected these waves on May 13th using a Sudden Ionospheric Disturbance monitor in Milan, Italy:

Sudden ionospheric disturbances--"SIDs" for short--make themselves known by the effect they have on low-frequency radio signals. When a SID passes by, the atmosphere overhead becomes an good reflector for radio waves, allowing signals to be received from distant transmitters. Battaiola monitored a faraway 21.75 kHz radio station to monitor the SIDs over his location.

More SIDS are in the offing as NOAA forecasters estimate an 80% chance of M-flares and a 50% chance of X-flares during the next 24 hours. Solar flare alerts: text, voice.

Realtime Solar Eclipse 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 16, 2013 there were 1397 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Miss Distance
2013 JR7
May 10
9.1 LD
18 m
2013 JM22
May 16
7.9 LD
95 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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