You are viewing the page for Sep. 25, 2008
  Select another date:
<<back forward>>
SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
SPACE WEATHER
Current conditions
Solar wind
speed: 336.3 km/sec
density: 6.8 protons/cm3
explanation | more data
Updated: Today at 2246 UT
X-ray Solar Flares
6-hr max: A0
1650 UT Sep25
24-hr: A0
1650 UT Sep25
explanation | more data
Updated: Today at: 2245 UT
Daily Sun: 25 Sep 08
Sunspot 1002 has faded away, leaving the sun blank. Credit: SOHO/MDI
Sunspot number: 0
What is the sunspot number?
Updated 24 Sept. 2008
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= 3 quiet
24-hr max: Kp= 3
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: 6.3 nT
Bz: 3.5 nT south
explanation | more data
Updated: Today at 2247 UT
Coronal Holes:
A solar wind stream flowing from the indicated coronal hole should reach Earth on or about Oct. 2nd. Credit: SOHO Extreme UV Telescope
SPACE WEATHER
NOAA Forecasts
Updated at: 2008 Sep 25 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 Sep 25 2201 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
01 %
01 %
MINOR
01 %
01 %
SEVERE
01 %
01 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
01 %
01 %
MINOR
01 %
01 %
SEVERE
01 %
01 %
What's up in Space
September 25, 2008
AURORA ALERTS: Did you miss the Northern Lights of August 9th? Next time get a wake-up call from Space Weather PHONE.  

CHINESE SPACE LAUNCH: China's Shenzhou 7 spacecraft carrying a 3-man crew lifted off today from the Jiuquan Satellite Launch Center and is now in Earth orbit. During the upcoming three-day mission, Chinese astronauts, called taikonauts, will launch a small satellite and conduct their country's first spacewalk. Shenzhou 7 and the body of the rocket that launched it will be visible to the naked eye as they orbit Earth. Check the Satellite Tracker for viewing times.

Sighting report: Shortly after launch, Shenzhou 7 and its rocket passed over Wainuiomata, New Zealand, where Robert Holdsworth saw them. "They went just below Orion with only about a second or so between them." Both were about as bright as first magnitude stars, he says.

LOW SOLAR WIND: The solar wind is losing power. That's the surprising conclusion of scientists working with data from the Ulysses spacecraft, which has been circling the sun in a polar orbit for nearly 20 years. During that time solar wind pressure has dropped more than 20%. Note the blue curve in the "clock plot" below:

Blue traces solar wind pressure now. For comparison, green traces the significantly higher pressure of the mid-1990s. How this difference fits into the big picture of solar activity over the centuries, no one knows, because solar wind measurements began only 50 years ago with the start of the Space Age. Early measurements were spotty and not always well-calibrated, so, in fact, we know the solar wind well for even less than 50 years. Consequences of low solar wind include fewer geomagnetic storms, more cosmic rays, and NASA's Voyager spacecraft exiting the solar system sooner than anyone expected. Get the full story from Science@NASA.

SUNRISE AT THE SOUTH POLE: On Sept. 21st, Ethan Dicks looked out the window of his office and saw the sun for the first time in 6 months. He quickly grabbed his camera and snapped this picture of sunrise at the South Pole:

"I am a researcher for the University of Wisconsin-Madison, running
IceCube, the large (1 km3 when completed) neutrino telescope that's under construction a mile below the ice near the South Pole," explains Dicks. "The past six months have been almost nothing but night; it's good to see the sun again."

He took the picture a full day before the Sept. 22nd equinox--the "official" date of sunrise. Geometrically, the sun should've been mostly below the horizon at the time, but refraction by the dense polar atmosphere lifted the image up for all to see.

"Polar regions are famous for mirages and early explorers sometimes wondered what was real and what illusion," notes atmospheric optics expert Les Cowley. "In Dicks' picture, several air layers of different temperature have distorted and sliced the sun. Its rays are bent as they pass between the layers to form multiple images, some inverted and some upright."

Dicks is a veteran observer of South Pole sunrises. "This is my third winter here," he says. Some sunrises are heralded weeks ahead of time by a diffuse glow on one side of the sky and the retreating shadow of Earth ("a dark blue band topped by a fringe of magenta") on the other. Eventually a sliver of sun appears, circling the horizon for days, growing in size, until finally the sun emerges in full. "When it's clear, the show is amazing. This year, we were mostly clouded out until Sept. 21st. I feel bad for folks on their first and maybe only winter-over; they missed the full sunrise."

When you're at the South Pole, though, even a fraction of sunrise can be a wonderous thing.

SOLAR WIND LOSING POWER: In a briefing yesterday at NASA HQ, solar physicists announced that the solar wind is losing pressure, hitting a 50-year record low for the Space Age. This development has repercussions across the solar system: full story.


Sept. 2008 Aurora Gallery
[Aurora Alerts] [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 September 25, 2008 , there were 981 potentially hazardous asteroids.
Sept. 2008 Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Mag.
Size
2003 WT153
Sept. 7
5.8 LD
23
11 m
1996 HW1
Sept. 12
53 LD
12
3.7 km
2003 SW130
Sept. 19
8.6 LD
23
7 m
1998 UO1
Sept. 26
25 LD
18
2.0 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.
©2013 Spaceweather.com. All rights reserved.