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SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
 
Solar wind
speed: 732.4 km/sec
density: 0.3 protons/cm3
explanation | more data
Updated: Today at 2345 UT
X-ray Solar Flares
6-hr max: C1
2242 UT Apr25
24-hr: C3
1215 UT Apr25
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 25 Apr 12
Sunspot 1465 has developed a "beta-gamma-delta" magnetic field that harbors energy for X-class solar flares. Credit: SDO/HMI
Sunspot number: 169
What is the sunspot number?
Updated 23 Apr 2012

Spotless Days
Current Stretch: 0 days
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

Updated 23 Apr 2012


The Radio Sun
10.7 cm flux: 142 sfu
explanation | more data
Updated 23 Apr 2012

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/POES
Planetary K-index
Now: Kp= 4 unsettled
24-hr max: Kp= 4
unsettled
explanation | more data
Interplanetary Mag. Field
Btotal: 5.4 nT
Bz: 4.5 nT north
explanation | more data
Updated: Today at 2346 UT
Coronal Holes: 24 Apr 12
There are no large coronal holes on the Earthside of the sun. Credit: SDO/AIA.
SPACE WEATHER
NOAA Forecasts
Updated at: 2012 Apr 25 2200 UTC
FLARE
0-24 hr
24-48 hr
CLASS M
20 %
20 %
CLASS X
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: 2012 Apr 25 2200 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
50 %
25 %
MINOR
20 %
10 %
SEVERE
10 %
05 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
40 %
30 %
MINOR
30 %
15 %
SEVERE
15 %
10 %
 
Wednesday, Apr. 25, 2012
What's up in space
 

Can you drop a probe on a comet? A new iPhone game from NASA's Jet Propulsion Laboratory puts you in control of the Rosetta spacecraft as it prepares to intercept Comet 67P/Churyumov-Gerasimenko. Download it now.

 
Comet Quest for iOS

CHANCE OF FLARES: Sunspot AR1465 has developed a 'beta-gamma-delta' magnetic field that harbors energy for X-class solar flares. Because of the sunspot's location near the middle of the solar disk, any eruptions will likely be Earth-directed. Solar flare alerts: text, phone.

QUIETING STORM, MORE TO COME: Earth's magnetic field is quieting after two straight nights of mild to moderate geomagnetic storms. At the height of the disturbance on April 23-24, auroras were spotted in more than a dozen US states including Michigan, Nebraska, Kansas, Wisconsin, North Dakota, South Dakota, Iowa, Illinois, Minnesota, and Colorado. On the threshold of the Arctic Circle in Anchorage, Alaska, the Northern Lights pierced the glow of the midnight sun:

"I didn't think I would get another glimpse of the auroras this season because of the increasing daylight," says photographer Ryan Delos Reyes, "but this was a spectacular show."

More auroras may be in the offing. A minor CME is en route to Earth, due to arrive on April 26th. NOAA forecasters estimate a 20% to 30% chance of geomagnetic storms. Aurora alerts: text, phone.

SIERRA FIREBALL DECODED: On Sunday morning, April 22nd, just as the Lyrid meteor shower was dying down, a spectacular fireball exploded over California's Sierra Nevada mountain range. The loud explosion rattled homes from central California to Reno, Nevada, and beyond. According to Bill Cooke, head of NASA's Meteoroid Envronment Office, the source of the blast was a meteoroid about the size of a minivan.

"Elizabeth Silber at Western University has searched for infrasound signals from the explosion," says Cooke. "Infrasound is very low frequency sound which can travel great distances. There were strong signals at 2 stations, enabling a triangulation of the energy source at 37.6N, 120.5W. This is marked by a yellow flag in the map below."

"The energy is estimated at a whopping 3.8 kilotons of TNT, so this was a big event," he continues. "I am not saying there was a 3.8 kiloton explosion on the ground in California. I am saying that the meteor possessed this amount of energy before it broke apart in the atmosphere. [The map] shows the location of the atmospheric breakup, not impact with the ground."

"The fact that sonic booms were heard indicates that this meteor penetrated very low in atmosphere, which implies a speed less than 15 km/s (33,500 mph). Assuming this value for the speed, I get a mass for the meteor of around 70 metric tons. Hazarding a further guess at the density of 3 grams per cubic centimeter (solid rock), I calculate a size of about 3-4 meters, or about the size of a minivan."

"This meteor was probably not a Lyrid; without a trajectory, I cannot rule out a Lyrid origin, but I think it likely that it was a background or sporadic meteor."

News and eyewitness reports: #1, #2, #3, #4.

  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 25, 2012 there were 1287 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Mag.
Size
2012 HE
Apr 22
6.9 LD
--
31 m
2012 HE2
Apr 24
8.9 LD
--
28 m
2012 HQ
Apr 24
9.8 LD
--
42 m
2012 HP13
Apr 27
2 LD
--
64 m
2012 HM
Apr 28
1.4 LD
--
67 m
2011 WV134
Apr 28
38.6 LD
--
1.6 km
1992 JD
May 2
9.5 LD
--
43 m
2010 KK37
May 19
2.3 LD
--
31 m
4183 Cuno
May 20
47.4 LD
--
5.7 km
2002 VX94
May 26
72.8 LD
--
1.1 km
2002 AC
Jun 16
62.2 LD
--
1.2 km
1999 BJ8
Jun 16
68.8 LD
--
1.1 km
2005 GO21
Jun 21
17.1 LD
--
2.2 km
2003 KU2
Jul 15
40.3 LD
--
1.3 km
2004 EW9
Jul 16
46.8 LD
--
2.1 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.
STEREO
  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
Heliophysics
  the underlying science of space weather
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