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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: 443.1 km/s
4.9 protons/cm3
explanation | more data
Updated: Today at 2246 UT

X-ray Solar Flares
6-hr max:
B3 2245 UT Apr24
24-hr: B3 2245 UT Apr24
explanation | more data
Updated: Today at 2245 UT

Daily Sun: 24 Apr '07

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

Sunspot Number: 0
What is the sunspot number?
Updated: 23 Apr 2007

Far Side of the Sun

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

Interplanetary Mag. Field
Btotal: 5.7 nT
3.5 nT north
explanation | more data
Updated: Today at 2246 UT

Coronal Holes:

A solar wind stream flowing from the indicated coronal hole should hit Earth on April 28th. 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 24 2203 UTC
FLARE 0-24 hr 24-48 hr
CLASS M 01 % 01 %
CLASS X 01 % 01 %

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 24 2203 UTC
0-24 hr 24-48 hr
ACTIVE 05 % 05 %
MINOR 01 % 01 %
SEVERE 01 % 01 %

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

What's Up in Space -- 24 Apr 2007
Subscribe to Space Weather News

What's the name of that star? Where's Saturn? Get the answers from mySKY--a fun new astronomy helper from Meade.

SOLAR ACTIVITY: After days of quiet, the sun's eastern limb is suddenly alive with prominences. "What a pleasure to observe our fantastic star from Earth," says Franck Charlier of Val d'Oise, France, who took this picture using his Coronado SolarMax40. The activity may herald the approach of an active region just around the bend. Stay tuned.

3D SUN: Grab your 3D glasses. NASA has released the first batch of 3-dimensional sun photos taken by the STEREO spacecraft. This anaglyph shows a polar plume:

Plumes are towers of gas held together by solar magnetic fields. They rise out of coronal holes, persisting for a day or so before fading away again. Matter inside a plume is 20 to 30 times denser than outside, and it is thought that this dense material is spewing away from the sun. Plumes are not a major source of solar wind, but they may contribute substantial currents to the overall pattern of diffuse wind from the sun. It's a mystery which 3D views from from STEREO may help solve. Click here for more 3D images.

3D GLASSES: Build them at home or buy them online.

A FLOATING CITY: "The sunset tonight was spectacular!" says Pete Lawrence of Selsey, UK. "As the sun descended behind the silhouetted city of Portsmouth, its contents appeared to pour beneath the buildings producing a pool of fire."

Photo details: Canon 10D, Skywatcher ED80 (prime focus), ISO 100, 1/250s

While the city appears to be floating on fire, it is actually hot air that produces this mirage. Atmospheric optics expert Les Cowley explains: "Downward sun rays are bent gently upwards again by a layer of hot air close to the water. This causes a second inverted sun to appear beneath the 'real' one.--a classic inferior mirage. The town buildings are equally mirrored."

"While all this was was happening," adds Lawrence, "bits and pieces of sun were detaching from the top and distorting. It was an amazing thing to watch." More images: #1, #2, #3, #4.

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 24 Apr 2007 there were 858 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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