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<<back forward>> -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
Current conditions
Solar wind
speed: 444.5 km/sec
density: 6.9 protons/cm3
explanation | more data
Updated: Today at 2346 UT
X-ray Solar Flares
6-hr max: A0
2340 UT Aug19
24-hr: A0
2340 UT Aug19
explanation | more data
Updated: Today at: 2340 UT
Daily Sun: 19 Aug 09
The sun is blank--no sunspots. Photo credit: SOHO/MDI
Sunspot number: 0
What is the sunspot number?
Updated 18 Aug 2009

Spotless Days
Current Stretch: 39 days
2009 total: 181 days (79%)
Since 2004: 692 days
Typical Solar Min: 485 days
explanation | more info
Updated 18 Aug 2009

Far side of the Sun:
This holographic image reveals no sunspots on the far side of the sun. Image credit: SOHO/MDI
Planetary K-index
Now: Kp= 3 quiet
24-hr max: Kp= 3
explanation | more data
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Interplanetary Mag. Field
Btotal: 10.0 nT
Bz: 2.5 nT north
explanation | more data
Updated: Today at 2346 UT
Coronal Holes:
There are no large coronal holes on the Earth-facing side of the sun. Credit: SOHO Extreme UV Telescope
NOAA Forecasts
Updated at: 2009 Aug 19 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: 2009 Aug 19 2201 UTC
0-24 hr
24-48 hr
25 %
10 %
05 %
01 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
30 %
15 %
10 %
01 %
01 %
01 %
What's up in Space
August 19, 2009

AURORA ALERT: Did you miss the Northern Lights? In July they descended as far south as Nebraska. Next time get a wake-up call: Spaceweather PHONE.


SOLAR ACTIVITY: Today in England, Les Cowley looked at the minimum sun with little hope of seeing anything interesting. "I was very pleasantly surprised to find an impressive prominence," he says. Readers with solar telescopes, point your optics at the northwestern limb of the sun.

JUPITER MOON MOVIE: Four hundred years ago when Galileo discovered the moons of Jupiter, the satellites appeared in his primitive telescope as tiny, almost infinitesimal specks of light pirouetting around the giant planet. Their discovery transformed 17th century cosmology and made Galileo famous, but he never saw them as anything more than star-like pinpricks. The "Galilean satellites" were second-class citizens in the heirarchy of known worlds.

What would Galileo say now?

On August 16th, Philippine astrophotographer Christopher Go used a modern 11-inch Celestron telescope to photograph Io casting its shadow on Ganymede. Click on the image to launch the movie:

"I captured this rare event through a hole in the clouds," says Go. "It was a lucky clearing!"

In the movie, Io and Ganymede reveal themselves as fully-formed worlds with surface markings and a spherical shape. Io's circular shadow cuts a dark swath across Ganymede, transforming that giant moon (it is larger than Mercury) into a succession of crescents rarely seen by observers. Indeed, as far as we know, no telescope on Earth or space has ever photographed one of Jupiter's moons casting its circular shadow so clearly across another.

"While imaging the shadow transit, I took the time to photograph Jupiter itself," says Go. "The Great Red Spot, an anticyclone twice the size of Earth, was very prominent."

At this point, one imagines Galileo would jump up and exclaim--"bring me a telescope!" If only we could. August 2009 is a superb time to watch the giant planet. Jupiter is at its closest to Earth and outshines every star in the night sky. Backyard optics reveal giant storms, clouds, moons, moon shadows and occasionally an explosive surprise. The place to look is here.

UNRULY STAR TRAILS: When a photographer points his camera at the North Celestial Pole and opens the shutter, stars are supposed to make long, graceful arcs around Polaris. They're called "star trails." On August 11th, some of the stars did not cooperate:

That's because they were shooting stars. "I took the picture during the Perseid meteor shower," says Tom Warner of Rapid City, South Dakota. "It is an all-night composite of 20-second exposures from my Nikon D700. The bright Moon is visible along with some of the brighter Perseids cutting across the star trails."

Browse the gallery for updated images of the best Perseid shower since 1993:

2009 Perseid Photo Gallery
[Science@NASA: The Perseids are Coming, Horse Flies and Meteors]

2009 Noctilucent Photo Gallery
[previous years: 2008, 2007, 2006, 2005, 2004, 2003]

Explore the Sunspot Cycle

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 August 19, 2009 there were 1067 potentially hazardous asteroids.
August 2009 Earth-asteroid encounters:
Miss Distance
2009 MC9
Aug. 7
70.3 LD
1.2 km
2009 OF
Aug. 8
15.4 LD
220 m
2007 RQ17
Aug. 9
8.4 LD
130 m
2000 LC16
Aug. 17
75.6 LD
2.0 km
2006 SV19
Aug. 21
59.2 LD
1.3 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 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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