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SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
SPACE WEATHER
Current conditions
Solar wind
speed: 380.1 km/sec
density: 0.3 protons/cm3
explanation | more data
Updated: Today at 2346 UT
X-ray Solar Flares
6-hr max: A5
1935 UT Apr18
24-hr: B1
0205 UT Apr18
explanation | more data
Updated: Today at: 2340 UT
Daily Sun: 18 Apr. 10
The Earth-facing side of the sun is blank--no sunspots. Credit: SOHO/MDI
Sunspot number: 0
What is the sunspot number?
Updated 17 Apr 2010

Spotless Days
Current Stretch: 3 days
2010 total: 10 days (9%)
2009 total: 260 days (71%)
Since 2004: 780 days
Typical Solar Min: 485 days
explanation | more info
Updated 17 Apr 2010


The Radio Sun
10.7 cm flux: 74 sfu
explanation | more data
Updated 17 Apr 2010

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/POES
Planetary K-index
Now: Kp= 0 quiet
24-hr max: Kp= 1
quiet
explanation | more data
Interplanetary Mag. Field
Btotal: 4.4 nT
Bz: 0.3 nT south
explanation | more data
Updated: Today at 2347 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 18 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 18 2201 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
05 %
05 %
MINOR
01 %
01 %
SEVERE
01 %
01 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
10 %
10 %
MINOR
01 %
01 %
SEVERE
01 %
01 %
What's up in Space
April 18, 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.

 

DOUBLE FLYBYS: Space shuttle Discovery has undocked from the International Space Station in advance of a Monday morning landing at the Kennedy Space Center. Sky watchers should be alert for double flybys as the two spaceships circle Earth together. Check the Simple Satellite Tracker for viewing opportunities or, if you have an iPhone, download the app.

double flyby images: from Robert Hoetink of Enschede, The Netherlands; from Sietse Dijkstra of Lattrop, The Netherlands.

RARE SHUTTLE RE-ENTRY: On Monday morning, April 19th, space shuttle Discovery will make a rare "descending node" overflight of the continental United States en route to landing in Florida. Many towns and cities in the country's heartland are near the ground track:

UPDATE! How to predict sighting
opportunities for your location

Landing is scheduled for 8:48 am EDT, and it takes the shuttle about 35 minutes to traverse the path shown above. Observers in the northwestern USA will see the shuttle shortly after 5 am PDT blazing like a meteoritic fireball through the dawn sky. As Discovery makes its way east, it will enter daylight and fade into the bright blue background. If you can't see the shuttle, however, you might be able to hear it. The shuttle produces a sonic double-boom that reaches the ground about a minute and a half after passing overhead.

Check nasa.gov for more maps. A forecast of cloud cover along the ground track is also available.

previous reentry images: from Alan Dyer of near Gleichen, Alberta, Canada

VOLCANIC LIGHTNING: It is well known that volcanic eruptions produce strong lightning. Less well known is why? Ordinary lightning in thunderstorms is not fully understood; volcanic lightning is even more of a mystery.

To investigate, a team of researchers from New Mexico Tech has traveled to Iceland to monitor the Eyjafjallajokull volcano--and they have found it crackling with electricity:

"On the evening of April 16th, there were some small eruptions producing ash clouds up to about 6-7 km, with lightning," says photographer Harald Edens. "The sky was nice and clear, so I was able to photograph the bolts from the town of Hvolsvollur using my Nikon D700 and a 80-200/2.8 lens."

Photography is one way to monitor volcanic lightning, but the technique has limits: Ash clouds are able to hide the flashes; lightning is not always visible in daylight; glowing lava competes for attention; and so on. 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 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 18, 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...
   
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