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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: 356.3 km/sec
density: 8.5 protons/cm3
explanation | more data
Updated: Today at 2244 UT
X-ray Solar Flares
6-hr max: A0
2245 UT Sep17
24-hr: A0
0320 UT Sep17
explanation | more data
Updated: Today at: 2245 UT
Daily Sun: 17 Sep 07
The sun is blank--no sunspots. Credit: SOHO/MDI
Sunspot number: 0
What is the sunspot number?
Updated 15 Sep 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= 1
quiet
explanation | more data
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/POES
Updated: 2007 Sep 17 2132 UT
Interplanetary Mag. Field
Btotal: 4.5 nT
Bz: 0.7 nT north
explanation | more data
Updated: Today at 2246 UT
Coronal Holes:
A solar wind stream flowing from the indicated coronal hole should reach Earth on Sept. 21st or 22nd. Credit: Hinode X-Ray Telescope
SPACE WEATHER
NOAA Forecasts
Updated at: 2007 Sep 17 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 Sep 17 2203 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
10 %
10 %
MINOR
05 %
05 %
SEVERE
01 %
01 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
15 %
15 %
MINOR
10 %
10 %
SEVERE
01 %
01 %
What's up in Space
September 17, 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. .

BRIGHT THREESOME: When the sun goes down tonight, step outside and look south. Jupiter, a fat crescent Moon and the red giant star Antares are gathered together in the constellation Scorpius. The three are bright enough to see even from light polluted cities. Take a look: sky map.

AURORA WATCH: Japan's Hinode spacecraft is monitoring a gaping hole in the sun's atmosphere--a "coronal hole"--that is spewing solar wind into space. It is the enormous black gash in this image from Hinode's onboard x-ray telescope:

The sun is rotating (once every 27 days) and soon the hole will face Earth, causing a stream of solar wind to sweep past our planet on Sept. 21st or 22nd. High-latitude sky watchers should be alert for auroras.

September 2007 Aurora Gallery
[August 2007 Aurora Gallery] [Aurora Alerts]

UNDERWATER RAINBOWS: Is it possible to have a rainbow ... underwater? Snorkeling photographer Mila Zinkova found them everywhere during a recent swim around Kona, Hawaii. "Christmas tree sea worms were surrounded by beautiful bright 'bows and even a mean-looking moray eel was framed by corals and rainbows." But not everything that looks like a rainbow really is. What Mila really photographed were rainbow-colored caustics. (continued below)


more images: #1, #2, #3, #4

Atmospheric optics expert Les Cowley explains: "Caustics are the bright lines and curves we see criss-crossing the bottom of any sunlit shallow seabed. They are formed by the water's rippling surface, which behaves like a collection of liquid lenses. Light rays passing through the lenses bunch to make the caustics. Lenses bend blue rays more strongly than red and this, combined with interference between the ray paths, makes the colors."

"Caustics are everywhere," he adds. "Look for them in swimming pools, your bathtub and even in your coffee cup."

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 September 17, 2007 there were 886 potentially hazardous asteroids.
Sept. 2007 Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Mag.
Size
2007 RF1
Sep. 2
8.5 LD
18
26 m
2007 RS1
Sep. 5
0.2 LD
17
3 m
2007 RJ1
Sep. 16
2.5 LD
16
40 m
2007 RC20
Sep. 20
5.1 LD
19
22 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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