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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: 673.4 km/sec
density: 0.8 protons/cm3
explanation | more data
Updated: Today at 2245 UT
X-ray Solar Flares
6-hr max: A0
2245 UT Oct25
24-hr: A0
2245 UT Oct25
explanation | more data
Updated: Today at: 2245 UT
Daily Sun: 25 Oct 07
The sun is blank--no sunspots. Credit: SOHO/MDI
Sunspot number: 0
What is the sunspot number?
Updated 24 Oct 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= 5 mild
24-hr max: Kp= 6
moderate
explanation | more data
Current Auroral Oval:

Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/POES
Updated:
What is the auroral oval?
Interplanetary Mag. Field
Btotal: 4.7 nT
Bz: 3 nT south
explanation | more data
Updated: Today at 2247 UT
Coronal Holes:
Earth is inside a solar wind stream flowing from the indicated coronal hole. Credit: Hinode X-ray Telescope
SPACE WEATHER
NOAA Forecasts
Updated at: 2007 Oct 25 2135 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 Oct 25 2135 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
35 %
20 %
MINOR
20 %
15 %
SEVERE
10 %
05 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
35 %
25 %
MINOR
25 %
20 %
SEVERE
15 %
05 %

What's up in Space
October 25, 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.

AURORA ALERT: A geomagnetic storm is underway that could spark auroras bright enough to see through the glare of tonight's full Moon. High latitude obervers should be alert for Northern Lights.

SPACESHIP SIGHTINGS: Last night when the International Space Station flew over Texas, photographer Bret Dahl pointed his 10" LX200 at the moving point of light and took this amazing picture. The ISS has grown so large, its details are easily resolved by ordinary backyard telescopes. Tonight the details are different: space shuttle Discovery has docked to the ISS making the ensemble even bigger and brighter. Be alert for flybys.

STRANGE COMET: Astronomers around the world agree, Comet 17P/Holmes is one of the strangest things ever to explode in the night sky. It's a comet, yet it looks like a planet with a golden core and a green atmosphere:

Chris Shur of Payson, Arizona, took this picture last night using his 12.5-inch telescope and a Canon XTi digital camera. "The comet was yellow and green, very bright in the viewfinder," he says.

Yesterday, Comet Holmes shocked sky watchers with a spectacular eruption, brightening almost a million-fold from 17th to 2.5th magnitude in a matter of hours. The comet is now visible to the naked eye--even from light polluted cities--high in the northern sky after sunset: finder chart.

The golden hue of Holmes' core is probably the color of sunlight scattered by comet dust, while the green fringe likely signifies an atmosphere rich in diatomic carbon and cyanogen (substances found in many green comets). There are reports that the fuzzball is expanding and taking on a lopsided shape--the first signs of a tail? Amateur astronomers are encouraged to monitor developments. After sunset, point your backyard telescope at the extra "star" in the thigh of Perseus.

Comet 17P/Holmes Photo Gallery
[sky map] [ephemeris] [3D orbit] [Night Sky Cameras]

BIG FULL MOON: Tonight's full Moon is the biggest full Moon of 2007. It's no illusion. Some full Moons are genuinely larger than others and this one is a whopper. Why? Read the answer below.


Left: A big, bright perigee Moon. RIght: A lesser apogee Moon.

The Moon's orbit is an ellipse with one side 30,000 miles closer to Earth than the other. The full Moon of Oct. 25-26 is located on the near side, making it appear as much as 14% bigger and 30% brighter than lesser full Moons we've seen earlier in 2007.

In the language of astronomy, the two ends of the Moon's orbit are called "apogee" and "perigee." Apogee is the farthest point, perigee the nearest: diagram. This week's full Moon is a "perigee Moon" with extra-high "perigean tides."

The Moon is 14% bigger, but can you actually tell the difference? It's not so easy. There are no rulers floating in the sky to measure lunar diameters. A fun experiment: Take a friend outside tonight and ask if they notice anything unusual about the Moon. Explain perigee after they answer.


October 2007 Aurora Gallery
[September Gallery] [Aurora Alerts]

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 25, 2007 there were 894 potentially hazardous asteroids.
Oct.-Nov. 2007 Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Mag.
Size
2007 TL16
Oct. 5
1.6 LD
16
27 m
2007 TC14
Oct. 18
11.7 LD
17
180 m
2340 Hathor
Oct. 22
23.3 LD
16
620 m
2005 GL
Nov. 8
8.0 LD
16
280 m
1989 UR
Nov. 24
27.6 LD
15
880 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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