You are viewing the page for Dec. 21, 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: 288.5 km/sec
density: 1.1 protons/cm3
explanation | more data
Updated: Today at 2246 UT
X-ray Solar Flares
6-hr max: A0
2245 UT Dec21
24-hr: A0
2245 UT Dec21
explanation | more data
Updated: Today at: 2245 UT
Daily Sun: 21 Dec 08
The sun is blank--no sunspots. Credit: SOHO/MDI

more images: from Guenter Kleinschuster of Feldbach, Styria, Austria
Sunspot number: 0
What is the sunspot number?
Updated 18 Dec. 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= 0 quiet
24-hr max: Kp= 1
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: 2.9 nT
Bz: 1.9 nT north
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 Dec. 22nd. Credit: SOHO Extreme UV Telescope
SPACE WEATHER
NOAA Forecasts
Updated at: 2008 Dec 21 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 Dec 21 2201 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
20 %
15 %
MINOR
05 %
01 %
SEVERE
01 %
01 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
20 %
15 %
MINOR
05 %
01 %
SEVERE
01 %
01 %
What's up in Space
December 21, 2008

For less than the cost of a night at the movies, you can give someone the heavens for Christmas. Now available: gift subscriptions to Spaceweather PHONE.

 

URSID METEORS: Earth is entering a stream of debris from comet 8P/Tuttle and this is causing the annual Ursid meteor shower. Forecasters expect the Ursids to peak on Dec. 22nd with 8 to 10 meteors per hour flying out of the constellation Ursa Minor (the Little Dipper). The display is usually mild, but outbursts of Ursids occasionally surprise observers with rates many times normal.

Watching these northern meteors can be a chilling experience, so why not stay inside and listen to them instead? Spaceweather.com is broadcasting live audio from the Air Force Space Surveillance Radar in Texas. When a meteor passes over the radar--"ping"--there is an echo. Give it a try; feedback is welcomed.

SOLSTICE WEBCAST: Today is the northern winter solstice. When the solstice sun came up this morning over Ireland, a shaft of sunlight traveled down an 18 meter tunnel to illuminate the inner chamber of Newgrange, a massive prehistoric burial mound in County Meath. It looked like this:

Newgrange is 5000 years old, predating the better-known Stonehenge in the neighboring island of Great Britain by more than a thousand years. This makes it one of the oldest megalithic monuments in the world with a known astronomical function. Curators of Newgrange webcast this morning's event; you can watch it here.

There is a similar burial mound from the same era in Orkney: Like Newgrange, Maeshowe is also aligned with the solstice sun. As the midwinter sun slips below the horizon, its last rays shine directly through Maeshowe's entrance passage to illuminate the rear wall of the central chamber. Live images from Maeshowe may be found here.

WINTER SKY: Northern winter has begun, and that means Orion now rules the night sky. The mighty hunter rises in the east at sunset, towers overhead at midnight, and watches the sun rise astride the western horizon at dawn. Photographer P-M Hedén sends this photo entitled Orion and Me from Hedesunda, Sweden:

"What a lovely sky I had last night!" says Hedén, "It cleared up and the constellation of Orion was setting over the Dalriver outside Hedesunda. I hope that this will be the sight tonight when the Ursids are underway. I took the picture using my Canon Digital Rebel XT."


Dec. 2008 Aurora Gallery
[Previous Decembers: 2007, 2006, 2005, 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 December 21, 2008 there were 1011 potentially hazardous asteroids.
Dec. 2008 Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Mag.
Size
2008 WY94
Dec. 5
3.2 LD
19
35 m
2008 WG14
Dec. 5
4.8 LD
17
49 m
2008 XK
Dec. 6
1.7 LD
17
15 m
2008 XC1
Dec. 12
4.3 LD
16
102 m
2008 XB2
Dec. 13
5.8 LD
18
47 m
2006 VB14
Dec. 14
36 LD
15
795 m
2008 EV5
Dec. 23
8.4 LD
13
435 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 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.