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Solar wind
speed: 399.0 km/sec
density: 1.0 protons/cm3
explanation | more data
Updated: Today at 2347 UT
X-ray Solar Flares
6-hr max: C1
1805 UT Apr15
24-hr: C1
1403 UT Apr15
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 15 Apr 13
Sunspots AR1718 and AR1719 have 'beta-gamma' magnetic fields that harbor energy for M-class solar flares. Credit: SDO/HMI
Sunspot number: 111
What is the sunspot number?
Updated 15 Apr 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

15 Apr 2013

The Radio Sun
10.7 cm flux: 117 sfu
explanation | more data
Updated 15 Apr 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: 5.8 nT
Bz: 0.5 nT south
explanation | more data
Updated: Today at 2347 UT
Coronal Holes: 15 Apr 13
A coronal hole is emerging over the sun's SE limb. Solar wind flowing from the hole could reach Earth on April 20-21. Credit: SDO/AIA.
NOAA Forecasts
Updated at: 2013 Apr 15 2200 UTC
0-24 hr
24-48 hr
25 %
15 %
05 %
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 Apr 15 2200 UTC
0-24 hr
24-48 hr
10 %
10 %
01 %
01 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
15 %
15 %
20 %
15 %
10 %
05 %
Monday, Apr. 15, 2013
What's up in space

When is the best time to see auroras? Where is the best place to go? And how do you photograph them? These questions and more are answered in a new book, Northern Lights - a Guide, by Pal Brekke & Fredrik Broms.

Northern Lights - a Guide

DARK MATTER ON THE ISS: A particle detector on board the International Space Station has recorded intriguing signs of Dark Matter that could reveal what the mysterious substance is made of. If the finding holds up, it could lead to significant advances in cosmology. [full story] [video]

CME IMPACT: A coronal mass ejection (CME) hit Earth's magnetic field on April 13th. The impact was not a strong one; geomagnetic activity never crossed storm thresholds. Nevertheless, the impact sparked faint auroras photographed in several northern-tier US states. Brian Larmay sends this exposure from Beecher, Wisconsin:

"I got up at 230 am CST to see if the auroras had made their way south, and I saw a glow that looked to he naked eye like light pollution," says Larmay. "My camera revealed the colors. I didn't expect much of a display because the CME impact was rather weak--but there it was."

"I have noticed that the southern hemisphere of the sun is starting to pepper more with spots," he continues. Indeed, the southern hemisphere has been lagging behind the north in sunspot production, and it might be starting to catch up. A surge in southern sunspot production would boost solar activity. "This is good news for the aurora chasers," Larmay opines, and he is right! Aurora alerts: text, voice.

Realtime Aurora Photo Gallery

3D ANTI-CREPUSCULAR RAYS: Yesterday, near sunset, Larry Perkins was driving along highway I-25 north of Walsenberg, Colorado, when he saw a pair of dark rays lance across the sky. Using the motion of the car to change his perspective, he was able to photograph several stereo pairs. Cross your eyes to see the phenomenon in 3D:

The technical term for the phenomenon is "anticrepuscular rays"--that is, cloud shadows that point away from the setting sun.

"Slowly cross your eyes until the shadows merge," advises Perkins. "I find the shape of the lenticular cloud creating the rays as interesting as the rays themselves. The cloud is cylindrical and shrouded in a thin foggy shell."

Note: If you have trouble seeing the 3D effect in the small images, above, try these larger pairs instead.

Realtime Space Weather Photo Gallery

Realtime Aurora Photo Gallery

Realtime Comet 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 April 15, 2013 there were 1395 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Miss Distance
2013 GB55
Apr 12
9.8 LD
31 m
2013 GT66
Apr 13
7.1 LD
38 m
2010 GM23
Apr 13
3.9 LD
50 m
2013 GH66
Apr 15
4 LD
10 m
2013 GJ69
Apr 15
7.8 LD
23 m
2013 GH23
Apr 19
5.5 LD
32 m
2005 NZ6
Apr 29
24.9 LD
1.3 km
2001 DQ8
Apr 30
74.3 LD
1.1 km
2004 BV102
May 25
69.9 LD
1.4 km
1998 QE2
May 31
15.2 LD
2.1 km
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
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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