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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: 366.7 km/sec
density: 2.4 protons/cm3
explanation | more data
Updated: Today at 2245 UT
X-ray Solar Flares
6-hr max: A0
2245 UT Oct24
24-hr: A0
2245 UT Oct24
explanation | more data
Updated: Today at: 2245 UT
Daily Sun: 24 Oct 07
The sun is blank--no sunspots. Credit: SOHO/MDI
Sunspot number: 0
What is the sunspot number?
Updated 23 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= 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 Oct 24 2054 UT
What is the auroral oval?
Interplanetary Mag. Field
Btotal: 4.0 nT
Bz: 1.3 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 Oct. 25th or 26th. Credit: Hinode X-ray Telescope
SPACE WEATHER
NOAA Forecasts
Updated at: 2007 Oct 24 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 Oct 24 2203 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
30 %
35 %
MINOR
15 %
20 %
SEVERE
05 %
10 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
35 %
40 %
MINOR
25 %
30 %
SEVERE
15 %
20 %

What's up in Space
October 24, 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.

SPACESHIP SIGHTINGS: Space shuttle Discovery is chasing the ISS around Earth and they're a beautiful sight in the night sky. Witness this picture taken last night by Bryan Tobias of San Antonio, Texas. "The ISS came first and then Discovery 12 minutes later," says Tobias. The two ships will converge on Oct. 24th in preparation for docking on Oct. 25th. Be alert for flybys.

HOT NEWS: Astronomers in Japan, Persia and Europe report that Comet 17P/Holmes is undergoing a spectacular eruption. The 17th magnitude comet has brightened by a factor of five hundred thousand or more during the past 24 hours becoming a naked-eye object in the evening sky. Look for a yellow 2.5th magnitude fuzzball in the constellation Perseus after sunset. [sky map] [ephemeris] [3D orbit]

"This is unbelievable!" says Iranian astronomer Babak Tafreshi. "I was amazed to find Comet Holmes so easily with the naked-eye in the light-polluted skies of metropolitan Tehran." Click on Tafreshi's photo to pinpoint the comet:

The outburst may signify a breakup of the comet's core or a rich vein of ice suddenly exposed to sunlight--no one knows. At present the comet looks more like a star than a comet; it does not have a discernable tail, but it might grow one as the outburst continues. Amateur astronomers are encouraged to monitor developments using binoculars and backyard telescopes. Stay tuned for updates!

more images: from P-M Hedén of Vallentuna, Sweden; from Vladimir Ladinsky of Moscow, Russia; from Martin McKenna of Magheram Co. Derry, N. Ireland; from Runar Sandnes of Reed, Norway; from Ernesto Guido and Giovanni Sostero using a remote-controlled telescope in New Mexico.

BIG FULL MOON: This week's full Moon is the biggest full Moon of 2007. It's no illusion. Some full Moons are genuinely larger than others and Thursday night's will be 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 Thursday night 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 24, 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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