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<<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: 346.3 km/s
1.2 protons/cm3
explanation | more data
Updated: Today at 2224 UT

X-ray Solar Flares

6-hr max:
C3 2215 UT Dec18
24-hr: C7 0930 UT Dec18
explanation | more data
Updated: Today at 2245 UT

Daily Sun: 18 Dec '03
None of these small sunspots pose a threat for strong solar flares. Image credit: SOHO MDI

The Far Side of the Sun

This holographic image reveals perhaps one large sunspot group on the far side of the sun. Image credit: SOHO/MDI

Sunspot Number: 92
What is the sunspot number?
Updated: 17 Dec 2003

Interplanetary Mag. Field
Btotal: 4.3 nT
1.8 nT south
explanation | more data
Updated: Today at 2246 UT

Coronal Holes:

A solar wind stream flowing from the indicated coronal hole could reach Earth on Dec. 21st. Image 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 2003 Dec 18 2200 UTC
FLARE 0-24 hr 24-48 hr
CLASS M 20 % 20 %
CLASS X 05 % 05 %

Geomagnetic Storms: Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm
Updated at 2003 Dec 18 2200 UTC
0-24 hr 24-48 hr
ACTIVE 45 % 45 %
MINOR 20 % 20 %
SEVERE 05 % 05 %

High latitudes
0-24 hr 24-48 hr
ACTIVE 40 % 40 %
MINOR 25 % 30 %
SEVERE 10 % 10 %

What's Up in Space -- 18 Dec 2003
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AURORA OUTLOOK: Geomagnetic activity is low now, but it will likely increase on Dec. 21st when Earth runs into a solar wind stream flowing from a coronal hole on the sun. First contact with the stream could spark auroras at high latitudes.

DIAMOND DUST: Ordinarily, rainbow-colored sundogs appear high in the sky among the icy clouds that create them. But in some places, like Alaska, they can materialize right in front of you. Here's an example, photographed by Lesa Hollen of Fairbanks, Alaska, on Dec. 16th:

"The rainbow colors were brilliant and had a mystical effect with the Northface of the Alaskan Range silhouetted in the background," she says.

Sundogs like this are caused by diamond dust. Atmospheric optics expert Les Cowley explains: "When it is very cold (air temperature below freezing) large ice crystals, called diamond dust, can sometimes float nearby in the air.  The halos they form appear to be in front of distant hills or trees.  They also sparkle as the individual ice crystals glint in the sun."

DUST STORM ON MARS: With three space probes set to land on Mars in the weeks ahead, astronomers are keeping careful track of an ongoing martian dust storm. It began last week and has since grown large enough for amateur astronomers to see through backyard telescopes. For instance, Ed Grafton of Texas took this picture on Dec. 18th using a 14-inch 'scope and a CCD camera.

more images of Mars on Dec 13th, 14th and 16th from Don Parker; Dec. 15th and 18th from Ed Grafton; and Dec. 16th from Joel Warren.

A curious side-effect of the storm is the increasing brightness of Mars. "Mars was about 0.17 magnitudes brighter on Dec. 15th," says ALPO executive director Richard Schmude, Jr. "This increase is due to [sunlight reflected by] dust." For comparison, a global dust storm in 2001 caused Mars to brighten by 0.25 magnitudes.

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 are on a collision course with our planet, although astronomers are finding new ones all the time.

On 18 Dec 2003 there were 550 known Potentially
Hazardous Asteroids

November 2003 Earth-asteroid encounters


2003 UC20

Dec 2

32 LD

2003 XJ7

Dec 6

0.4 LD

2003 WY25

Dec 12

10 LD

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 --a gallery of up-to-date solar pictures from the National Solar Data Analysis Center at the Goddard Space Flight Center. See also the GOES-12 Soft X-ray Imager.

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

SOHO Farside Images of the Sun from SWAN and MDI.

The Latest SOHO Coronagraph Images -- from the Naval Research Lab

The Sun from Earth -- daily images of our star from the Big Bear Solar Observatory

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

Observable Comets -- from the Harvard Minor Planet Center.

What is the Interplanetary Magnetic Field? -- A lucid answer from the University of Michigan. See also the Anatomy of Earth's Magnetosphere.

Real-time Solar Wind Data -- from NASA's ACE spacecraft. How powerful are solar wind gusts? Read this story from Science@NASA.

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

Aurora Forecast --from the University of Alaska's Geophysical Institute

Daily Solar Flare and Sunspot Data -- from the NOAA Space Environment Center.

Lists of Coronal Mass Ejections -- from 1998 to 2001

What is an Iridium flare? See also Photographing Satellites by Brian Webb.

Vandenberg AFB missile launch schedule.

What is an Astronomical Unit, or AU?

Mirages: Mirages in Finland; An Introduction to Mirages;

NOAA Solar Flare and Sunspot Data: 1999; 2000; 2001; 2002; Jan-Mar., 2003; Apr-Jun., 2003;

Recent International Astronomical Union Circulars


Editor's Note: This site is sponsored by Science@NASA. Space weather and other forecasts that appear here are formulated by Dr. Tony Phillips. They should not be construed as guarantees of space weather or other celestial activity.

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