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: 24 Jan '07

Sunspot 939 poses no threat for strong solar flares. Credit:

Sunspot Number:
What is the sunspot number?

Far Side of the Sun

This holographic image reveals a southern spot on the far side of the sun. It may be old friend, sunspot 930, which sparked strong auroras in Dec. 2006. 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 will reach Earth on or about Jan. 29th. 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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Did you sleep through the auroras of Dec. 14th? Next time get a wake-up call: Spaceweather PHONE.

LUNAR TRANSIENTS: If you stared at the Moon for 107 hours, what would you see? About 60 satellites, an airplane, one ordinary meteor and 20 lunar explosions. That's the count according to a group of NASA astronomers who have just released their best videos of these "transient lunar phenomena." Get the full story from Science@NASA.

COMET MCNAUGHT: Another typical night in New Zealand--stars, clouds, an airplane and the brightest comet in 40 years! On the island of Wairarapa, last night, photographer Chris Picking made this movie of Comet McNaught setting in the west:

Photo details: Canon 10D, 18mm lens, f/4, ISO 800, 1-min exposures

Comet McNaught is visible from all parts of the Southern Hemisphere. No finder chart is required--simply look west after sunset. "What a spectacle!" says Hannes Pieterse of Bloemfontein, South Africa. "The mammoth tail stretches all the way past Venus: image."

Comet McNaught Photo Gallery
[ephemeris] [orbit] [comet binoculars]

MAGNETIC EMERGENCE: First, watch this movie of sunspot 939, which sprang into being over the weekend. To the human eye, the newborn spot looks like a growing blob of dark-brown matter. Not so. Sunspots are made of pure magnetism--no solid matter is involved.

A magnetogram onboard the Solar and Heliospheric Observatory (SOHO) shows what's really happening:

On Jan. 20th, two magnetic poles emerged from within the sun. Those poles are the infrastructure of sunspot 939. Intense magnetism around the poles blocks the flow of solar heat from below, creating a cool region on the sun's surface. To human eyes, this region appears dark because it is not as hot as its surroundings. Yes, you knew it all along, sunspots are cool!

Keep track of sunspot 939's cool inner magnetism at the SOHO website.

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 832 known Potentially
Hazardous Asteroids

Jan 2007 Earth-asteroid encounters




2006 UQ17

Jan. 2

11 LD


175 m
1991 VK

Jan. 21

26 LD


2.0 km
5011 Ptah

Jan. 21

77 LD


1.6 km
2006 CJ

Jan. 31

10 LD


385 m
2006 AM4

Feb. 1

5.2 LD


180 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: 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