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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: 440.2 km/s
1.8 protons/cm3
explanation | more data
Updated: Today at 2245 UT

X-ray Solar Flares
6-hr max:
A0 2210 UT Apr23
24-hr: A0 2210 UT Apr23
explanation | more data
Updated: Today at 2245 UT

Daily Sun: 23 Apr '07

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

Sunspot Number: 0
What is the sunspot number?
Updated: 22 Apr 2007

Far Side of the Sun

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

Interplanetary Mag. Field
Btotal: 5.1 nT
3.2 nT north
explanation | more data
Updated: Today at 2246 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 23 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 23 2203 UTC
0-24 hr 24-48 hr
ACTIVE 15 % 10 %
MINOR 05 % 05 %
SEVERE 01 % 01 %

High latitudes
0-24 hr 24-48 hr
ACTIVE 20 % 15 %
MINOR 05 % 05 %
SEVERE 01 % 01 %

What's Up in Space -- 23 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.

AURORA WATCH: Sky watchers from Scandinavia to Alaska should be alert for auroras tonight. A solar wind stream is buffeting Earth's magnetic field, and this could cause a geomagnetic storm.

3D SUN: Grab your 3D glasses. NASA has just released the first batch of 3-dimensional sun photos taken by the STEREO spacecraft. This image, for instance, reveals three dark holes in the sun's atmosphere:

Click on the image for a full-sized view

The "holes" are coronal holes, places where the sun's magnetic field opens up and allows solar wind to escape. Earth is inside a solar wind stream flowing from one of these coronal holes today. 3D imagery allows scientists to peer inside coronal holes and divine their structure, possibly leading to better space weather forecasts.

More 3D images!

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

NOT A LYRID: Last Friday night, April 20th, at 11 pm MDT, a brilliant fireball streaked over western Colorado. "Witness reports for the event began pouring in almost immediately, mostly from the Denver area," says Chris Peterson whose all-sky camera located in Guffey, Colorado, captured the meteor in flight:

Click for video!

Peterson points out the bright spot just north of the meteor. "That's the crescent Moon, which at 20% phase had a magnitude of -8.3. The meteor was much brighter than this."

Although the fireball occurred during the Lyrid meteor shower, it was not a Lyrid. Lyrids are meteors caused by dust in the tail of Comet Thatcher; they always appear to come from the constellation Lyra. "But the path of this fireball did not intersect Lyra," notes Peterson.

Astronomers call this kind of fireball a "sporadic." It was caused by a random fragment of comet or asteroid probably the size of a grapefruit. The inner solar system is littered with such fragments, and they hit Earth often. Sporadic fireballs as bright as this one appear somewhere on our planet about once a day.

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 23 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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