Science news and information about the Sun-Earth environment.


Solar Wind
speed: km/s
explanation | more data
Updated: Today at UT

X-ray Solar Flares
6-hr max:
24-hr: UT
explanation | more data
Updated: Today at UT

Daily Sun: 15 Dec '06

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

Sunspot Number:
What is the sunspot number?

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: nT
explanation | more data
Updated: Today at UT

Coronal Holes:

A solar wind stream flowing from the indicated coronal hole could reach Earth on or about Dec. 19th. 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
FLARE 0-24 hr 24-48 hr

Geomagnetic Storms: Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm
Updated at
0-24 hr 24-48 hr

High latitudes
0-24 hr 24-48 hr

What's Up in Space --
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MORE TO COME? A coronal mass ejection (CME) hit Earth yesterday and sparked a strong display of auroras. Another CME may be on the way. An X1-flare from sunspot 930 on Dec. 14th probably hurled a new cloud in our direction. (Confirmation from SOHO is pending.) If so, it would arrive on Dec. 16th and re-energize geomagnetic activity. Stay tuned!

AURORA ALERT: A strong geomagnetic storm is in progress. If it's dark where you live, go outside and look for auroras. And if you don't see them, try taking a picture. A 30-second exposure will often reveal colorful auroras that the human eye cannot see.

These auroras over Kalamazoo, Michigan, last night were plainly visible to the unaided eye:

"We're so lucky!" says photographer Richard Bell. "First, we get to observe the Geminid meteor shower on Wednesday then we get more Geminids and a nice aurora display on Thursday."

December 2006 Aurora Gallery

SOLAR RADIO BURSTS: The latest X-flare from sunspot 930 (an X1.5 explosion at 22:15 UT on Dec. 14th) sent shock waves billowing through the sun's atmosphere. Those waves produced a cacophany of shortwave radio emissions. Thomas Ashcraft recorded some of them using his radio telescope in New Mexico: listen.

Above: A spectrogram of solar radio bursts on Dec. 14th. Courtesy: NASA's Radio Jove Program and the University of Florida Radio Observatory (UFRO).

"We were lucky to catch a slice of these powerful solar radio sweeps at 22 MHz while the Sun was still in our antenna beams," says Ashcraft.

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 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