SPACE WEATHER
Current conditions
Solar wind
speed: 442.5 km/sec
density: 0.5 protons/cm3
explanation | more data
Updated: Today at 2325 UT
X-ray Solar Flares
6-hr max: A3
2310 UT Apr21
24-hr: A3
1135 UT Apr21
explanation | more data
Updated: Today at: 2325 UT
Daily Sun: 21 Apr. 10
The Earth-facing side of the sun is blank--no sunspots. This is the sixth day in a row with no visible sunspots, the longest stretch of the year so far. Credit: SOHO/MDI
Sunspot number: 0
What is the sunspot number?
Updated 20 Apr 2010

Spotless Days
Current Stretch: 6 days
2010 total: 13 days (11%)
2009 total: 260 days (71%)
Since 2004: 783 days
Typical Solar Min: 485 days
explanation | more info
Updated 20 Apr 2010


The Radio Sun
10.7 cm flux: 75 sfu
explanation | more data
Updated 20 Apr 2010

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/POES
Planetary K-index
Now: Kp= 1 quiet
24-hr max: Kp= 2
quiet
explanation | more data
Interplanetary Mag. Field
Btotal: 4.3 nT
Bz: 2.2 nT north
explanation | more data
Updated: Today at 2326 UT
Coronal Holes:
A solar wind stream flowing from the indicated coronal hole(s) could reach Earth on or about April 22nd. Credit: SOHO Extreme UV Telescope
SPACE WEATHER
NOAA Forecasts
Updated at: 2010 Apr 21 2201 UTC
FLARE
0-24 hr
24-48 hr
CLASS M
01 %
01 %
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: 2010 Apr 21 2201 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
25 %
20 %
MINOR
10 %
05 %
SEVERE
01 %
01 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
30 %
15 %
MINOR
15 %
05 %
SEVERE
05 %
01 %
What's up in Space
April 21, 2010

NEW AND IMPROVED: Turn your iPhone or iPod Touch into a field-tested global satellite tracker. The Satellite Flybys app now works in all countries.

 

LYRID METEOR SHOWER: The Lyrid meteor shower peaks on April 22nd when Earth passes through a stream of debris from Comet Thatcher (C/1861 G1). The best time to look is during the hours before dawn on Thursday morning. Forecasters expect as many as 20 meteors per hour. [full story] [fireball movie]

STUNNING IMAGES OF THE SUN: NASA's Solar Dynamics Observatory is beaming back stunning new images of the sun, revealing our own star as never seen before. Even veteran solar physicists say they are amazed by the data. Click on the prominence, below, to see what everyone is so excited about:


Must-see movies and images!

Related links:

VOLCANIC LIGHTNING: Iceland's active Eyjafjallajokull volcano is famous for its paralyzing ash, which has grounded thousands of planes in Europe and disrupted travel worldwide. Even more amazing, however, is its white-hot lightning:

"Seeing this lightning crackle among the exploding lava and ash was the experience of a lifetime," says Olivier Vandeginste, who took the picture on April 18th from Hvolsvollur, Iceland.

It is well known that volcanoes produce lightning, but scientists aren't sure why. The underlying mechanism is likely to be some form of triboelectric charging--that is, things bumping or rubbing together (like socks rubbing on carpet) to create a build-up of static electricity. That's how it works in sand storms and even ordinary thunderstorms. In a volcano, the "rubbing things" may be bits of ash and droplets of lava, although no one is certain.

To investigate, a team of researchers from New Mexico Tech has arrived in Iceland to study the phenomenon. Photography is not their primary method, however. Cameras are limited to what they can see through the heavy clouds of ash. Radio receivers can do a better job. Lightning emits impulsive radio bursts which can be measured and counted, day or night, even through clouds of ash. "We are deploying a six-station lightning mapping array around the Eyjafjallajokull volcano," says team member Harald Edens. Their analysis of the radio "crackles" could reveal much about the inner workings of volcanic lightning.


April Northern Lights Gallery
[previous Aprils: 2009, 2008, 2007, 2006, 2005, 2004, 2003, 2002]

 
       
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 21, 2010 there were 1116 potentially hazardous asteroids.
April 2010 Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Mag.
Size
2010 GV23
April 5
2.1 LD
19
12 m
2010 GF7
April 8
2.8 LD
18
30 m
2010 GA6
April 9
1.1 LD
16
27 m
2010 GM23
April 13
3.4 LD
17
47 m
2005 YU55
April 19
5.9 LD
15
185 m
2009 UY19
April 23
8.8 LD
18
87 m
2002 JR100
April 29
8.0 LD
19
65 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 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 and Heliospheric Observatory
  Realtime and archival images of the Sun from SOHO.
STEREO
  3D views of the sun from NASA's Solar and Terrestrial Relations Observatory
Daily Sunspot Summaries
  from the NOAA Space Environment Center
Current Solar Images
  from the National Solar Data Analysis Center
Science Central
   
  more links...
   
Cool links:
 
 
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©2008, SpaceWeather.com -- This site is penned daily by Dr. Tony Phillips.