You are viewing the page for Dec. 18, 2006
  Select another date:
<<back forward>> -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
Science news and information about the Sun-Earth environment.


Solar Wind
speed: 525.1 km/s
2.9 protons/cm3
explanation | more data
Updated: Today at 2245 UT

X-ray Solar Flares
6-hr max:
A4 1720 UT Dec18
24-hr: B1 0005 UT Dec18
explanation | more data
Updated: Today at 2245 UT

Daily Sun: 18 Dec '06

Departing sunspot 930 has a "beta-gamma-delta" magnetic field that harbors energy for X-class solar flares. Credit:

Sunspot Number: 11
What is the sunspot number?
Updated: 17 Dec 2006

Far Side of the Sun

This holographic image reveals no large sunspots on the far side of the sun. Image credit: SOHO/MDI

Interplanetary Mag. Field
Btotal: 6.2 nT
1.6 nT south
explanation | more data
Updated: Today at 2247 UT

Coronal Holes:

A solar wind stream flowing from the indicated coronal hole could reach Earth on Dec. 20th. Credit: SOHO Extreme UV Telescope


Solar Flares: Probabilities for a medium-sized (M-class) or a major (X-class) solar flare during the next 24/48 hours are tabulated below.
Updated at 2006 Dec 18 2204 UTC
FLARE 0-24 hr 24-48 hr
CLASS M 05 % 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 2006 Dec 18 2204 UTC
0-24 hr 24-48 hr
ACTIVE 15 % 20 %
MINOR 05 % 10 %
SEVERE 01 % 05 %

High latitudes
0-24 hr 24-48 hr
ACTIVE 20 % 40 %
MINOR 05 % 15 %
SEVERE 01 % 10 %

What's Up in Space -- 18 Dec 2006
Subscribe to Space Weather News

Would you like a call when auroras appear over your hometown? Sign up for Spaceweather PHONE.

URSID METEOR SHOWER: A flurry of meteors may emerge from Ursa Minor (the Little Dipper) on Dec. 22nd between 18 and 23 hours UT when Earth runs into a filament of debris trailing comet 8P/Tuttle. Meteor forecaster Peter Jenniskens of the SETI Institute anticipates as many as 39 meteors per hour, best seen from Europe and Asia. Reference: IAU Electronic Telegram #773.

AURORAS FROM SPACE: How bright were the auroras of Dec. 14th? As bright as city lights and easily seen from space. A US Air Force DMSP satellite took this picture from orbit 830 km above the United States:

The bright arc stretching from Montana to Maine is the aurora borealis. In many places it completely overwhelms the city lights below.

"The DMSP satellite has the ability to detect auroral light at night," says Paul McCrone of the Air Force Weather Agency at Offutt AFB in Nebraska. "These images are mosaics of various DMSP overflights on Dec. 12-13, Dec. 13-14, and Dec 14-15. The Dec. 14th image is quite striking."

December 2006 Aurora Gallery
Updated: December 18th

GOODBYE... and thanks for all the X-flares. Sunspot 930 announced itself on Dec. 5th with one of the strongest flares in years--an X9, followed by an X6 on Dec. 6th, an X3 on Dec. 13th, and an X1 on Dec. 14th. Not bad for solar minimum!

Now the spot is gone. The slow spin of the sun carried it over the sun's western limb this morning--but not before one last flare:

Photo details: Coronado PST and a Canon XTI digital camera.

"Today sunspot 930 said a nice goodbye," reports photographer Mila Zinkova of San Francisco, California. "There was C2 flare at the limb with a nice ring-shaped prominence. The prominence changed shape and brightness constantly--very pretty."

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 18 Dec 2006 there were 836 known Potentially
Hazardous Asteroids

Dec 2006 Earth-asteroid encounters




2006 WQ127

Dec. 2

7.9 LD


~94 m
2006 WB

Dec. 5

7.0 LD


~130 m
2004 XL14

Dec. 20

10.1 LD


~225 m
Notes: LD is a "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 Web 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. (European Mirror Site)

Daily Sunspot Summaries -- from the NOAA Space Environment Center.

Current Solar Images -- from the National Solar Data Analysis Center

X-ray images of the Sun: GOES-12 and GOES-13

Recent Solar Events -- a summary of current solar conditions from

What is the Magnetosphere?

The Lion Roars -- visit this site to find out what the magnetosphere sounds like.

List of Potentially Hazardous Asteroids -- from the Harvard Minor Planet Center.

Observable Comets -- from the Harvard Minor Planet Center.

Real-time Solar Wind Data -- from NASA's ACE spacecraft.

How powerful are solar wind gusts? Not very! Read this story from Science@NASA.

More Real-time Solar Wind Data -- from the Solar and Heliospheric Observatory Proton Monitor.

Lists of Coronal Mass Ejections -- from 1996 to 2006

Mirages: Mirages in Finland; An Introduction to Mirages;

NOAA Solar Flare and Sunspot Data: 1996, 1997, 1998, 1999; 2000; 2001; 2002; 2003; 2004; 2005; Jan-Mar 2006; Apr-Jun 2006; Jul-Sep 2006; Oct-Dec 2006.

This site is penned daily by Dr. Tony Phillips: email

©2013 All rights reserved.