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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: 511.0 km/sec
density: 1.4 protons/cm3
explanation | more data
Updated: Today at 2246 UT
X-ray Solar Flares
6-hr max: A0
2245 UT Jul31
24-hr: A0
2245 UT Jul31
explanation | more data
Updated: Today at: 2245 UT
Daily Sun: 31 July 07
The sun is blank again--no sunspots. Credit: SOHO/MDI
Sunspot number: 13
What is the sunspot number?
Updated 30 July 2007
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= 1 quiet
24-hr max: Kp= 2
quiet
explanation | more data
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/POES
Updated: 2007 Jul 31 2144 UT
Interplanetary Mag. Field
Btotal: 4.0 nT
Bz: 1.6 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 Ultraviolet Telescope
SPACE WEATHER
NOAA Forecasts
Updated at: 2007 Jul 31 2203 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: 2007 Jul 31 2203 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
15 %
10 %
MINOR
05 %
01 %
SEVERE
01 %
01 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
25 %
15 %
MINOR
05 %
01 %
SEVERE
01 %
01 %
What's up in Space
July 31, 2007
Where's Saturn? Is that a UFO--or the ISS? What's the name of that star? Get the answers from mySKY--a fun new astronomy helper from Meade.

SUPER-BOLIDE: On Wednesday, July 25th at approximately 10:00 UT, "a major daylight fireball tore across the skies of Slovenia, Croatia and Italy," reports veteran meteor observer Jure Atanackov of Maribor, Slovenia. "It produced two bright flashes that reached an estimated magnitude of -20 and also loud sonic booms."

Magnitude -20? In plain language, the meteor was 600 times brighter than a full Moon. Atanackov has gathered reports from hundreds of eyewitnesses. "Most described the fireball as very bright, its surface brightness almost as great as the Sun's. One person said it was 'too bright to look at for more than a few moments.'"

Above: This is not the fireball. The image was posted by a Croatian news service as an example of what the fireball looked like. Non-speakers of Croatian misunderstood and widely circulated the photo as a genuine record of the event.

The July 25th fireball falls into the category of superbolides--exploding meteors of magnitude -17 or brighter. They are, essentially, small asteroids measuring a few to 10 meters in diameter and massing a few hundred metric tons. Superbolides trigger seismic detectors on the ground, produce waves of infrasound that can travel thousands of miles, and they are tracked by military satellites scanning Earth for nuclear explosions. Recent examples include the El Paso fireball of 1997 and the Yukon fireball of 2000.

Eyewitnesses, please report your sightings to Jure Atanackov or colleague Javor Kac who are gathering data to learn more about the "Slovenian Superbolide" and to estimate possible landing sites.

PROMINENCE ALERT: "What a nice surprise," says Mark Hanson of Middleton, Wisconsin. "This morning I was testing a new focal reducer for my SolarMax90 when these nice prominences popped up."

They may look like flames, but prominences are something different: gigantic clouds of hydrogen held together by solar magnetic fields. Shortly after Hanson snapped the photo, above, Robert Morlan of
La Porte, Indiana, caught the tallest prominence apparently breaking free: image. This happens sometimes when a prominence's magnetic field becomes unstable. Astronomers, now is the time to monitor developments.

more images: from N. Lowell, S. Hatfield and J. Stetson of South Portland, Maine; from P-M Hedén of Vallentuna, Sweden; from Tom Masterson of Ferndale, Washington; from Robert Arnold of Isle of Skye, Scotland; and a sketch from Les Cowley of the UK.


.2007 Noctilucent Cloud Gallery
[Night-Sky Cameras] ["Noctilucent Cloud"--the song]

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 31, 2007 there were 876 potentially hazardous asteroids.
July 2007 Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Mag.
Size
2007 FV42
July 2
53 LD
15
1.2 km
2007 MB4
July 4
7.6 LD
16
130 m
2007 DT103
July 29
9.3 LD
15
550 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 Environment 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...
©2007, SpaceWeather.com -- This site is penned daily by Dr. Tony Phillips.
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