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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: 622.2 km/sec
density: 1.4 protons/cm3
explanation | more data
Updated: Today at 2245 UT
X-ray Solar Flares
6-hr max: A0
2135 UT Apr23
24-hr: A4
1330 UT Apr23
explanation | more data
Updated: Today at: 2245 UT
Daily Sun: 23 Apr 08
Sunspot 992 poses no threat for strong solar flares. The magnetic field of this sunspot is now well characterized; the N-S pattern identifies it as an old-cycle rather than a new-cycle sunspot. Solar Cycle 23 remains active. Credit: SOHO/MDI
Sunspot number: 13
What is the sunspot number?
Updated 22 Apr 2008
Far side of the Sun:
This holographic image reveals no large sunspots on the farside of the sun. Image credit: SOHO/MDI
Planetary K-index
Now: Kp= 5 storm
24-hr max: Kp= 5
storm
explanation | more data
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/POES
What is the auroral oval?
Interplanetary Mag. Field
Btotal: 5.3 nT
Bz: 3.5 nT south
explanation | more data
Updated: Today at 2246 UT
Coronal Holes:
A solar wind stream flowing from the indicated coronal hole should reach Earth on or about April 25th. Credit: SOHO Extreme UV Telescope
SPACE WEATHER
NOAA Forecasts
Updated at: 2008 Apr 23 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: 2008 Apr 23 2203 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
45 %
35 %
MINOR
20 %
10 %
SEVERE
10 %
05 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
35 %
30 %
MINOR
30 %
20 %
SEVERE
20 %
10 %
What's up in Space
April 23, 2008
FLYBY ALERT! Would you like a phone call when the International Space Station (ISS) is about to fly over your back yard? Sign up for Space Weather PHONE.  

SOLAR CINEMA: On April 9th an enormous solar prominence erupted, sending twisted curls of magnetized plasma billowing away from the edge of the sun. NASA's STEREO spacecraft was watching and has beamed a movie of the blast back to Earth. Enjoy the show: 6 MB Quicktime, 3 MB mpeg, 110 kB snapshot.

GREEN SKY ALERT: Sky watchers around the Arctic Circle should be alert for auroras tonight. A solar wind stream is buffeting Earth's magnetic field and causing high-latitude geomagnetic storms. Yuichi Takasaka sends this picture from Lumby, British Columbia:

"I went outside to try out my telescope's new equatorial mount and found these green lights overhead," says Takasaka. Indeed, it often pays to look for green among the stars at this time of year. Why? Because spring is aurora season.

April 2008 Aurora Gallery
[Aurora Alerts] [Night-sky Cameras]

LUNAR FOGBOW: Amateur astronomer Krzysztof Polakowski woke up before dawn on April 21st to photograph the Lyrid meteor shower. It was a beautiful moonlit night in Gniewowo, Poland, with just one problem: a bank of fog rolled in and hid the sky. With little to do, Krzysztof fell asleep.

"Later, when I opened my eyes, I saw a strange light right in front of me. It had the shape of a rainbow, but very pale." He took this picture using his Nikon D70s:


Photo details: Nikon D70s, 25 s, ISO 1600, Zenitar 2.8 16mm, f/4.0

"Wow! What is this?" he asks.

Atmospheric optics expert les Cowley answers: "It is a lunar fogbow. Fogbows are like rainbows but made by light refracted through tiny fog droplets rather than large raindrops. They are broad, ghostly and almost colorless."

To see a lunar fogbow, you'll need a foggy, moonlit night. Go outside, face the moon, then spin around and look behind you. That's where the 'bow will be. "A golden rule of atmospheric optics is whenever there is something interesting in the sky check out the opposite direction," says Cowley. "You could find a rarity."



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. [comment]
On April 23, 2008 there were 946 potentially hazardous asteroids.
April 2008 Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Mag.
Size
2008 FH5
Apr. 2
7.6 LD
20
17 m
2001 QO142
Apr. 6
34 LD
17
685 m
2008 GF1
Apr. 7
0.8 LD
18
10 m
2005 BE2
Apr. 10
62 LD
18
1.0 km
2005 NB7
Apr. 17
16 LD
16
705 m
2008 FU6
Apr. 22
62 LD
16
1.4 km
2005 TB
Apr. 28
47 LD
18
1.3 km
2001 DQ8
Apr. 30
74 LD
17
1.1 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, SpaceWeather.com -- This site is penned daily by Dr. Tony Phillips.
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