You are viewing the page for Apr. 17, 2012
  Select another date:
<<back forward>>
SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
 
Solar wind
speed: 413.7 km/sec
density: 5.5 protons/cm3
explanation | more data
Updated: Today at 2345 UT
X-ray Solar Flares
6-hr max: B9
2225 UT Apr17
24-hr: C1
0815 UT Apr17
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 17 Apr 12
The source of yesterday's "spectacular explosion" is circled. It hardly looks capable of such a magnificent blast. Credit: SDO/HMI
Sunspot number: 86
What is the sunspot number?
Updated 16 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 16 Apr 2012


The Radio Sun
10.7 cm flux: 108 sfu
explanation | more data
Updated 16 Apr 2012

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/POES
Planetary K-index
Now: Kp= 3 quiet
24-hr max: Kp= 3
quiet
explanation | more data
Interplanetary Mag. Field
Btotal: 5.8 nT
Bz: 5.2 nT south
explanation | more data
Updated: Today at 2347 UT
Coronal Holes: 17 Apr 12
There are no large coronal holes on tthe Earthside of the sun. Credit: SDO/AIA.
SPACE WEATHER
NOAA Forecasts
Updated at: 2012 Apr 17 2200 UTC
FLARE
0-24 hr
24-48 hr
CLASS M
20 %
15 %
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 17 2200 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
10 %
10 %
MINOR
01 %
01 %
SEVERE
01 %
01 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
15 %
15 %
MINOR
15 %
15 %
SEVERE
10 %
10 %
 
Tuesday, Apr. 17, 2012
What's up in space
 

Metallic photos of the sun by renowned photographer Greg Piepol bring together the best of art and science. Buy one or a whole set. They make a stellar gift.

 
Metallic pictures of the Sun

LYRID METEOR SHOWER: Earth is approaching the debris field of ancient Comet Thatcher, source of the annual Lyrid meteor shower. Forecasters expect the shower to peak on April 21-22; a nearly-new moon on those dates will provide perfect dark-sky conditions for meteor watching. Usually the shower is mild (10-20 meteors per hour) but unmapped filaments of dust in the comet's tail sometimes trigger outbursts 10 times stronger. [video] [Lyrid chat]

SPECTACULAR EXPLOSION (UPDATED): Magnetic fields on the sun's northeastern limb erupted around 17:45 UT on April 16th, producing one of the most visually-spectacular explosions in years. NASA's Solar Dynamics Observatory (SDO) recorded the blast at extreme ultraviolet wavelengths:

.

The explosion, which registered M1.7 on the Richter Scale of solar flares, was not Earth-directed, but it did hurl a CME into space. Analysts at the Goddard Space Weather Lab have analyzed the trajectory of the cloud and found that it will hit NASA's STEREO-B spacecraft, the Spitzer space telescope, and the rover Curiosity en route to Mars. Planets Venus and Mars could also receive a glancing blow.

Using data from SDO, Steele Hill of NASA's Goddard Space Flight Center assembled a must-see movie of the event. It shows the explosion unfolding at 304Å, a wavelength which traces plasma with a temperature around 80,000 K.

Coverage of the blast was not limited to space telescopes. Amateur astronomers saw it, too. Jim Lafferty sends this picture from his backyard observatory in Redlands, California:

"Yesterday's prominence on the sun's eastern limb was was one of the largest in years---short lived, it was mostly gone in a few hours," says Lafferty. "It was a wonderful sight in the eyepiece and in the camera!"

more images: from Vahan Yeterian of Lompoc California; from John Minnerath of Crowheart, Wyoming; from John Stetson of Falmouth, Maine; from Thomas Ashcraft of New Mexico;

  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 17, 2012 there were 1287 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Mag.
Size
2012 GY11
Apr 14
9 LD
--
21 m
2012 GW11
Apr 18
4.9 LD
--
23 m
1996 SK
Apr 18
67.2 LD
--
1.6 km
2007 HV4
Apr 19
4.8 LD
--
8 m
2012 GP1
Apr 21
9 LD
--
26 m
2012 HE
Apr 22
6.9 LD
--
33 m
2012 HM
Apr 28
1.5 LD
--
80 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
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
Trade Show Displays
   
  more links...
©2010 Spaceweather.com. All rights reserved. This site is penned daily by Dr. Tony Phillips.
©2013 Spaceweather.com. All rights reserved.