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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: 280.2 km/sec
density: 2.1 protons/cm3
explanation | more data
Updated: Today at 2246 UT
X-ray Solar Flares
6-hr max: A0
2245 UT Oct18
24-hr: A6
1200 UT Oct18
explanation | more data
Updated: Today at: 2245 UT
Daily Sun: 18 Oct 08
New-cycle sunspot 1006 is disappearing over the sun's western limb. Credit: SOHO/MDI
Sunspot number: 11
What is the sunspot number?
Updated 17 Oct. 2008
Far side of the Sun:
This holographic image reveals one possible sunspot on the far side of the sun. Image credit: SOHO/MDI
Planetary K-index
Now: Kp= 0 quiet
24-hr max: Kp= 0
quiet
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: 3.6 nT
Bz: 3 nT south
explanation | more data
Updated: Today at 2247 UT
Coronal Holes:
There are no coronal holes on the Earth-facing side of the sun. Credit: Hinode X-ray Telescope.
SPACE WEATHER
NOAA Forecasts
Updated at: 2008 Oct 18 2201 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 Oct 18 2201 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
10 %
10 %
MINOR
01 %
01 %
SEVERE
01 %
01 %
What's up in Space
October 18, 2008
BEHOLD THE SUN: Would you like to see fiery prominences and new-cycle sunspots with your own eyes? On sale now: Personal Solar Telescopes.  

A NEW KIND OF PULSAR: NASA's Fermi Gamma-ray Space Telescope has discovered a new kind of pulsar that hints at a previously unsuspected population of stars waiting to be found in the Milky Way: full story.

MONSTER PROMINENCE: Readers, if you have a solar telescope, train it on the sun. A prominence is surging over the sun's northeastern limb and "it's a monster," reports Pete Lawrence. He sends this picture from his backyard observatory in Selsey, UK:

"It's so big that I couldn't fit it all in one frame--a stunning arch of plasma that now appears to be reaching back towards the surface at the other end," he says.

more images: from Emiel Veldhuis of Zwolle, the Netherlands; from Cai-Uso Wohler of Bispingen, Germany; from Denis Joye of Boulonge, France; from James Screech of Bedford, England; from Stephen Ames of Hodgenville, Kentucky;

PURPLE SUNSETS: "Sunsets in recent evenings have had a delicate purple color," reports William Helms of Buena Vista, Colorado. "This is not their usual color. Is there some particulate matter in the atmosphere?"

The answer is "yes." Lingering aerosols from Alaska's Kasatochi volcano are producing sunsets like this:

"In the foreground is Mt. Princeton, a little over 14,000 feet in elevation," says Helms. "I took the photograph with a Canon PowerShot A710 in automatic mode and I did not enhance it in any way."

Why purple? It's a mixture of red and blue. The blue likely comes from volcanic particles in the stratosphere small enough to act as Rayleigh scatterers. Rayleigh scattering by air molecules turns the daytime sky blue; likewise, Rayleigh scattering by volcanic aerosols adds blue to the sunset. Mix that volcanic blue with a dash of ordinary sunset red and voila!--a purple sunset. (Note: This explanation should be considered speculative. The exact purple-producing mechanism is not well understood.)

When Kasatochi erupted on August 7th, it pumped more than a million tons of ash and sulfur dioxide into the stratosphere. Much of that material is still there, drifting around the Northern Hemisphere producing sunsets of subtle beauty. If don't see one tonight, look again tomorrow. The volcanic clouds are patchy and you may have to look many evenings in a row to catch the purple.

more images: from Doug Zubenel of De Soto, Kansas; from Jonathon Stone of Auburn, Alabama;


Oct. 2008 Aurora Gallery
[Previous Octobers: 2007, 2006, 2004, 2003, 2002, 2001, 2000]

       
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 October 18, 2008 there were 990 potentially hazardous asteroids.
Oct. 2008 Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Mag.
Size
2008 QS11
Oct. 2
11 LD
14
470 m
2008 SH148
Oct. 4
5.8 LD
19
26 m
2005 GN59
Oct. 6
20 LD
15
1.4 km
2008 TC3
Oct. 7
IMPACT
-13
3 m
2008 TZ
Oct. 10
5.3 LD
18
37 m
1999 VP11
Oct. 16
72 LD
17
860 m
2001 UY4
Oct. 18
74 LD
17
1.1 km
Comet Barnard-Boattini
Oct. 22
75 LD
16
unknown
2008 TT26
Oct. 23
3.6 LD
15
70 m
2000 EX106
Oct. 23
69 LD
18
1.1 km
2005 VN
Oct. 29
4.1 LD
15
116 m
4179 Toutatis
Nov. 9
20 LD
14
3.8 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 space weather bureau
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.
STEREO
  3D views of the sun from NASA's Solar and Terrestrial Relations Observatory
Daily Sunspot Summaries
  from the NOAA Space Environment Center
Current Solar Images
  from the National Solar Data Analysis Center
Science Central
  a one-stop hub for all things scientific
  more links...
   
©2008, SpaceWeather.com -- This site is penned daily by Dr. Tony Phillips.
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