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<<back forward>> -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
Current conditions
Solar wind
speed: 393.0 km/sec
density: 0.2 protons/cm3
explanation | more data
Updated: Today at 2344 UT
X-ray Solar Flares
6-hr max: C1
1935 UT Apr30
24-hr: C1
1935 UT Apr30
explanation | more data
Updated: Today at: 2340 UT
Daily Sun: 30 Apr. 10
Yesterday's small sunspot has faded away, but another one may be forming in the sun's northeastern quadrant. Credit: SOHO/MDI
Sunspot number: 0
What is the sunspot number?
Updated 29 Apr 2010

Spotless Days
Current Stretch: 1 day
2010 total: 21 days (17%)
2009 total: 260 days (71%)
Since 2004: 791 days
Typical Solar Min: 485 days
explanation | more info
Updated 29 Apr 2010

The Radio Sun
10.7 cm flux: 76 sfu
explanation | more data
Updated 29 Apr 2010

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Planetary K-index
Now: Kp= 0 quiet
24-hr max: Kp= 2
explanation | more data
Interplanetary Mag. Field
Btotal: 2.5 nT
Bz: 1.1 nT south
explanation | more data
Updated: Today at 2149 UT
Coronal Holes:
A solar wind stream flowing from the indicated coronal hole could reach Earth on or about May 3rd. Credit: STEREO-B Extreme UV Telescope
NOAA Forecasts
Updated at: 2010 Apr 30 2201 UTC
0-24 hr
24-48 hr
01 %
01 %
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 30 2201 UTC
0-24 hr
24-48 hr
05 %
05 %
01 %
01 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
05 %
05 %
01 %
01 %
01 %
01 %
What's up in Space
April 30, 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.


SUNSPOTS AHOY! Amateur astronomer Thomas Ashcraft of New Mexico reports a bipolar sunspot group forming in the sun's northeastern quadrant. He took these photos on April 30th around 1730 UT. Readers with solar telescopes are encouraged to monitor developments.

OVER THE SOUTH POLE: Night has fallen over the South Pole, and the hardy scientists who are "wintering over" there are enjoying a spectacular sky show. "For one thing, we are now seeing auroras," reports J. Dana Hrubes, leader of the South Pole Telescope Station. He snapped this picture on April 23rd using a Canon 7D:

But that's not all. Look at the streaks of light. "Those are satellites," says Hrubes. "Polar orbiting satellites all cross at the poles, so our skies get very crowded." Indeed, he says, it can be hard to photograph auroras without catching a satellite in the exposure.

More than a hundred satellites pass over Earth's poles on a daily basis. Polar orbits are widely used for military reconnaisance, Earth science, and weather monitoring--but the most common type of polar satellite is the Iridium comsat. Sixty-six of them swarm around Earth, providing voice and data coverage to satellite phones and pagers over the planet's entire surface.

The South Pole turns out to be a great place to observe Iridium flares. "We see them all the time," says Hrubes. "Here's one just above the South Pole Telescope and here's another passing through the Southern Cross."

With almost five more months of darkness ahead, the show is just getting started. Stay tuned for more from the South Pole.

THE TREE OF AVATAR: NASA's Solar Dynamics Observatory (SDO) is doing more than just taking crisp pictures of the sun. It is revealing our star as a place of intense and sometimes even alien beauty. In today's image, we see "The Tree of Avatar."

Click on the image to launch a 25 MB Quicktime movie

The trunk of the tree is a twisted, gnarly pillar of magnetism containing hundreds of millions of tons of relatively cool plasma. The canopy is a cloud of million-degree gas. As solar physicists watched this tree on April 19th, it exploded, producing one of the biggest eruptions in years: movie.

The colors in the movie trace different temperatures. Reds are relatively cool (60,000 K - 80,000 K); blues and greens are hot (1,000,000 K - 2,200,000 K). The tree's cool trunk rapidly heats up as it rises into the blast, and the canopy cools down as it falls in pieces back to the sun. Go ahead and watch the movie again. Once is not enough!

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 30, 2010 there were 1116 potentially hazardous asteroids.
April 2010 Earth-asteroid encounters:
Miss Distance
2010 GV23
April 5
2.1 LD
12 m
2010 GF7
April 8
2.8 LD
30 m
2010 GA6
April 9
1.1 LD
27 m
2010 GM23
April 13
3.4 LD
47 m
2005 YU55
April 19
5.9 LD
185 m
2009 UY19
April 23
8.8 LD
87 m
2002 JR100
April 29
8.0 LD
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.
  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...
©2008, -- This site is penned daily by Dr. Tony Phillips.













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