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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: 554.6 km/s
1.2 protons/cm3
explanation | more data
Updated: Today at 2245 UT

X-ray Solar Flares
6-hr max:
B2 1750 UT Apr30
24-hr: B2 1540 UT Apr30
explanation | more data
Updated: Today at 2245 UT

Daily Sun: 30 Apr '07

The magnetic field of sunspot 953 is growing more complex, and it now harbors energy for X-class solar flares. Credit: SOHO/MDI

Sunspot Number: 18
What is the sunspot number?
Updated: 29 Apr 2007

Far Side of the Sun

This holographic image reveals one sunspot on the farside of the sun, mage credit: SOHO/MDI

Interplanetary Mag. Field
Btotal: 3.4 nT
0.1 nT north
explanation | more data
Updated: Today at 2247 UT

Coronal Holes:

Earth is inside a solar wind stream flowing from the indicated coronal hole. 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 2007 Apr 30 2203 UTC
FLARE 0-24 hr 24-48 hr
CLASS M 15 % 15 %
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 2007 Apr 30 2203 UTC
0-24 hr 24-48 hr
ACTIVE 20 % 15 %
MINOR 10 % 05 %
SEVERE 01 % 01 %

High latitudes
0-24 hr 24-48 hr
ACTIVE 25 % 20 %
MINOR 10 % 10 %
SEVERE 05 % 01 %

What's Up in Space -- 30 Apr 2007
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What's the name of that star? Where's Saturn? Get the answers from mySKY--a fun new astronomy helper from Meade.

SOLAR ACTIVITY: Sunspot 953 is seething with activity. Earlier today Les Cowley of England watched as a sinuous filament of light reached into the heart of the 'spot from a nearby region of the sun. "I made this sketch of the view through my Coronado SolarMax60," he says. "The activity is indicated by red arrows." So far, none of the changes have resulted in a big flare, but the situation is promising.

more images: from Emiel Veldhuis of Zwolle, the Netherlands; from Patrick Bornet of Saint Martin sur Nohain, Nièvre France; from Franck Charlier of Marines, Val d'Oise, France.

SUNSPOT SUNRISE: "Today the sunrise was very interesting," reports Günther Strauch of Borken, Germay. The sun was "strangely deformed" and marked by a dark blemish:

Photo details: Canon EOS 20D, Vixen refractor 100/1000 mm

The "blemish" is sunspot 953. Measuring five times the diameter of Earth, it is big enough to see with the unaided eye, and its delta-class magnetic field harbors energy for X-class solar flares. NOAA forecasters estimate a 5% chance of an X-flare in the next 24 hours.

The strange deformations are a mirage. Temperature inversions (warm layers of air overlaying colder layers) caused the atmosphere to behave as a distorting lens. As the sun ascended behind these layers, "the shape of the sun changed from second to second," says Strauch who snapped these pictures: #1, #2, #3, #4.

MOON HALOS: There's a full Moon this week (May 2nd at 10:09 UT to be precise), and that means it's time to watch out for Moon halos. Tim Thorpe photographed this one from Copeville, South Australia:

Photo details: Nikon D70, 10mm focal length, ISO 200, 10 seconds

"A thin veil of cirrus and the nearly-full Moon got together to create one of the best 'rings around the Moon' I have ever seen," says Thorpe.

The ring was formed by ice crystals in the clouds. Pencil-shaped crystals catch rays of moonlight and bend them into a rainbow-colored circle as shown. When you see a moon halo, be alert for moondogs, moon pillars and other exotic arcs, too. They're all made by ice in the sky.

Note: Winter weather is not required for these halos. Even if it is hot on the ground, clouds floating miles overhead can be freezing cold. Ice halos are, therefore, a year-round phenomenon.

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 30 Apr 2007 there were 859 known Potentially
Hazardous Asteroids

April 2007 Earth-asteroid encounters




2006 VV2

Mar. 31

8.8 LD


2 km
2007 FY20

Apr. 2

5.3 LD


50 m
2007 DS84

Apr. 14

16 LD


325 m
2007 GU1

Apr. 16

2.1 LD


45 m
2007 HA

Apr. 17

6.5 LD


300 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

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

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