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<<back forward>> -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
Current conditions
Solar wind
speed: 716.2 km/sec
density: 1.3 protons/cm3
explanation | more data
Updated: Today at 2245 UT
X-ray Solar Flares
6-hr max: A0
2245 UT Jul13
24-hr: A0
2245 UT Jul13
explanation | more data
Updated: Today at: 2245 UT
Daily Sun: 13 Jul 08
The sun is blank--no sunspots. Credit: SOHO/MDI
Sunspot number: 0
What is the sunspot number?
Updated 12 July 2008
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
What is the auroral oval?
Interplanetary Mag. Field
Btotal: 3.6 nT
Bz: 0.6 nT south
explanation | more data
Updated: Today at 2246 UT
Coronal Holes:
Earth is inside a solar wind stream flowing from the indicated coronal hole. Credit: SOHO Extreme UV Telescope
NOAA Forecasts
Updated at: 2008 Jul 13 2203 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: 2008 Jul 13 2203 UTC
0-24 hr
24-48 hr
20 %
15 %
05 %
05 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
25 %
20 %
10 %
05 %
01 %
01 %
What's up in Space
July 13, 2008
AURORA ALERTS: Did you miss the Northern Lights of June 25th? Next time get a wake-up call from Space Weather PHONE.  

AURORA WATCH: On July 12th a solar wind stream hit Earth and sparked a geomagnetic storm over Saskatchewan, Canada. "Alerted by a phone call from Spaceweather, I rushed outside and got some beautiful pictures of the auroras," says Bob Johnson of Saskatoon. Sky watchers should be alert for a repeat tonight; the solar wind continues to blow and NOAA forecasters estimate a 30% chance of high-latitude geomagnetic activity: gallery.

BINARY ASTEROID: Asteroid 2008 BT18 is gliding past Earth this weekend and astronomers have just discovered that it is a binary system. "The sizes of the two components are 600 m for the primary and >200 m for the secondary," says Lance Benner of JPL. "The primary looks spheroidal, but we don't yet know about the shape of the secondary." Benner and others using a giant radar in Arecibo, Puerto Rico, obtained this "delay-doppler" image of the pair on July 7th:

"We're also getting images from NASA's Goldstone radar in the Mojave desert of California," he adds. That radar is smaller than Arecibo but it is still registering a strong echo that should reveal much about the target, including the binary orbit, masses and bulk density of the components.

About 16% of all near-Earth asteroids are binaries, but only a handful have come this close. "2008 BT18 is giving us a good look at a double asteroid," says Benner. Studying the make-up and dynamics of these systems may help researchers figure out how to deflect binaries on a collision course with Earth. 2008 BT18 poses no threat, but some undiscovered binary asteroid, one day, might. "The Arecibo observatory, where 53% of all near-Earth binaries have been discovered, is crucial to these studies."

Southern hemisphere readers, you may be able to observe this double-rock using your own backyard telescope and CCD camera. At closest approach (1.4 million miles) on July 14th, 2008 BT18 will flit through Canis Major heading south and glowing like a 13th magnitude star: ephemeris, 3D orbit.

MARS ON THE MOVE: Put on your 3D glasses and behold ... a "moving rock" on Mars:

Click to view the complete scene

Graphic artist Patrick Vantunye of Belgium created the 3D anaglyph by combining right- and left-eye images from Phoenix's stereo camera. It shows a rock near the Mars lander's feet seemingly pushed some distance through the dusty soil. "It reminds me of the moving rocks of Racetrack Playa in Death Valley," says Vantuyne. Long held to be a mystery, those Death Valley rocks are now thought to travel by means of wind propulsion, skidding along a desert floor momentarily slick after rainstorms. What moved this Mars rock? Possibilities include Phoenix's landing thrusters, martian wind, a nudge from Phoenix's robotic arm, and of course the unknown. Solutions are welcomed.

SOLUTIONS: What made the rock move? "It's a Vastitas Borealis Gastropod," suggests reader Craig Weiss. That's longhand for northern martian snail, the solution offered independently by a number of readers. Other popular ideas, more serious ones, centered on the role of ice. Maybe the "rock" is made of frozen water, less dense than its rocky neighbors and more easily tumbled by Phoenix's landing thrusters. Sublimation of ice might produce some jetting action that would help the lump move along--like a little martian comet. Or maybe it is just what it appears to be: a small rock, less firmly planted in the soil than other nearby rocks, tumbled down a gentle slope by wind or thrusters. "Upon closer inspection, I think I have found the truth behind the moving rock," muses another reader, Jim Mahoney. "Click here and all will be revealed."

UPDATED: July 2008 Aurora Gallery
[Aurora Alerts] [Night-sky Cameras]

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 July 13, 2008 , there were 960 potentially hazardous asteroids.
July 2008 Earth-asteroid encounters:
Miss Distance
2003 YE45
July 13
16.5 LD
1.4 km
2008 BT18
July 14
5.9 LD
1.0 km
2003 LC5
July 15
62 LD
1.4 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 bureau for real-time monitoring of solar and geophysical events, research in solar-terrestrial physics, and forecasting solar and geophysical disturbances.
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.
Daily Sunspot Summaries
  From the NOAA Space Environment Center
Current Solar Images
  from the National Solar Data Analysis Center
  more links...
©2008, -- This site is penned daily by Dr. Tony Phillips.
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