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: 23 Mar '07

The sun is blank today--no sunspots. Credit: SOHO/MDI

Sunspot Number:
What is the sunspot number?

Far Side of the Sun

This holographic image reveals one large sunspot group 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 this coronal hole could reach Earth on March 25th. 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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The space shuttle flies in April. Would you like a call when it soars over your backyard? Spaceweather PHONE!

ASTEROID FLYBY: Asteroid 2006 VV2 is about to fly past Earth. On March 30th at 11 pm PDT the 2 km-wide space rock will streak through the constellation Leo only 2 million miles away glowing like a 9th-to-10th magnitude star. This makes it an easy target for backyard telescopes with CCD cameras. Observers in the Americas are favored. [ephemeris] [3D orbit]

CORONAL HOLE: A hole has opened up in the sun's atmosphere and solar wind is spilling out. It's a "coronal hole," colored black in this March 21st ultraviolet image from the Solar and Heliospheric Observatory (SOHO):

High-latitude geomagnetic storms are possible when the solar wind reaches Earth on March 24th or 25th. Sky watchers from Scandinavia to Alaska should be alert for auroras.

PLUTO ECLIPSE: On March 18th, Pluto eclipsed a dim red star in the constellation Sagittarius. Amateur astronomer Chris Peterson recorded the event from his backyard observatory in Guffey, Colorado:

"For about 5 minutes, the combined intensity (star+Pluto) dropped about 0.45 magnitudes as the planet's shadow passed my observatory." He used an SBIG ST-8 camera and a 12-inch LX200 telescope to obtain the light curve.

When a star goes behind Pluto, its light is not extinguished abruptly, as if hidden by a sharp edge, but rather gradually--a sign that Pluto is surrounded by a fuzzy layer of gas. Such eclipses, properly called "stellar occultations," are a valuable tool for astronomers studying Pluto's surprising atmosphere.

March 19th Solar Eclipse Gallery
Updated March 23, 2007

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 853 known Potentially
Hazardous Asteroids

March 2007 Earth-asteroid encounters




2007 EH

Mar. 11

0.5 LD


10 m
2007 EK

Mar. 13

0.7 LD


5 m
2006 VV2

Mar. 31

8.8 LD


2 km
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

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: 1994, 1995, 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