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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: 319.2 km/sec
density: 5.1 protons/cm3
explanation | more data
Updated: Today at 2244 UT
X-ray Solar Flares
6-hr max: A1
2100 UT Dec04
24-hr: A1
2100 UT Dec04
explanation | more data
Updated: Today at: 2245 UT
Daily Sun: 04 Dec 07
Tiny sunspot 977 poses no threat for strong solar flares. Credit: SOHO/MDI
Sunspot number: 13
What is the sunspot number?
Updated 03 Dec 2007
Far side of the Sun:
This holographic image reveals no large sunspots on the far side of the sun. Image credit: SOHO/MDI
Planetary K-index
Now: Kp= 0 quiet
24-hr max: Kp= 1
quiet
explanation | more data
Current Auroral Oval:

Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/POES
Updated: 2007 Dec 04 2144 UT
What is the auroral oval?
Interplanetary Mag. Field
Btotal: 4.1 nT
Bz: 2.3 nT south
explanation | more data
Updated: Today at 2245 UT
Coronal Holes:
A weak solar wind stream flowing from the indicated coronal hole could hit Earth on Dec. 5th. Credit: Hinode X-ray Telescope
SPACE WEATHER
NOAA Forecasts
Updated at: 2007 Dec 04 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 Dec 04 2203 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
05 %
05 %
MINOR
01 %
01 %
SEVERE
01 %
01 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
05 %
05 %
MINOR
01 %
01 %
SEVERE
01 %
01 %

What's up in Space
December 4, 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.

CELESTIAL TRIANGLE: Tomorrow morning, Dec. 5th, Venus, the crescent Moon and first-magnitude star Spica will gather together in the eastern sky just before sunrise. You don't need to go outside or even wake up 100%--just shuffle in your pajamas to an east-facing window and behold the triangle! The best time to look is around 5 am: sky map.

SIGHTINGS: If you live in the United States, this is a good week to see the International Space Station. The giant spacecraft is flying over many US towns and cities during the evening hours of Dec. 3rd-6th: flyby alerts. During a typical flyby, the station shines two or three times brighter than Sirius, the brightest star in the sky, making it a wonderful naked-eye object. The station also looks great through a backyard telescope:

"I never thought I would see so much detail," says Scott Adler who took the picture on Nov. 20th using his 10-inch 'scope in Wallsend, Australia. Prominent in the photo are the station's newly-extended P6 solar arrays and a glistening new set thermal radiators: labels. These new additions to the ISS make the station bigger and brighter than ever.

EXTRA: "Careful planning, plotting and waiting paid off for this photo of the International Space Station passing within a few degrees of Comet 17P/Holmes earlier this evening," says Becky Ramotowski of Tijeras, New Mexico. "The sky was cloud covered just moments before showtime!"

ISLAND MYSTERY: The sun was setting last Saturday on the Dutch Caribbean island of St. Maarten when a fan of shadowy rays sprang up from the horizon. They looked like ordinary sunset rays except for one thing--"the sun was on the opposite side of the sky!" says onlooker Stephen Thompson. Dumbfounded, he took this picture:


Photo details: Canon XTi, F6.7, 24mm, 1/90s exposure.

"I am more than eager to know what this is," he says.

The answer: Anti-crepuscular rays.

Behind Thomson's back, the setting sun dipped behind some ragged clouds. The edges of those clouds cast shadows--immense tubes of darkness--that arced all the way across the sky to converge on the opposite horizon. Such shadows are called anti-crepuscular rays.

Anti-crepuscular rays are not rare, but they are delicate and often go unnoticed. The next time you see shadows emerging from the sunset, turn around. There may be something beautiful waiting right behind your back.


Comet 17P/Holmes Photo Gallery
[Interactive World Map of Comet Photos]
[sky map] [ephemeris] [3D orbit] [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 December 4, 2007 there were 907 potentially hazardous asteroids.
Dec. 2007 Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Mag.
Size
2007 VD184
Dec. 9
7.8 LD
18
95 m
3200 Phaethon
Dec. 10
47 LD
14
5 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...
©2007, SpaceWeather.com -- This site is penned daily by Dr. Tony Phillips.
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