You are viewing the page for Apr. 22, 2007
  Select another date:
<<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: 425.6 km/s
3.8 protons/cm3
explanation | more data
Updated: Today at 2245 UT

X-ray Solar Flares
6-hr max:
A0 1700 UT Apr22
24-hr: A0 1700 UT Apr22
explanation | more data
Updated: Today at 2245 UT

Daily Sun: 22 Apr '07

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

Sunspot Number: 0
What is the sunspot number?
Updated: 21 Apr 2007

Far Side of the Sun

This holographic image reveals no sunspots on the far side of the sun. Image credit: SOHO/MDI

Interplanetary Mag. Field
Btotal: 11.5 nT
8.6 nT north
explanation | more data
Updated: Today at 2246 UT

Coronal Holes:

A solar wind stream flowing from the indicated coronal hole should reach Earth today or tomorrow. 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 22 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 22 2203 UTC
0-24 hr 24-48 hr
ACTIVE 25 % 20 %
MINOR 10 % 05 %
SEVERE 01 % 01 %

High latitudes
0-24 hr 24-48 hr
ACTIVE 30 % 20 %
MINOR 15 % 05 %
SEVERE 05 % 01 %

What's Up in Space -- 22 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. Earth is entering a solar wind stream, and this could cause a geomagnetic storm.

3D SUN: On Monday, April 23rd, NASA will release, for the first time, 3-dimensional photos of the sun taken by the STEREO spacecraft. Magnetic loops and prominences will practically leap out of your computer screen. These images will be displayed on big screens at museums and science centers around the USA (list) and posted on the internet. Get ready this weekend by buying or building some 3D glasses--and stay tuned for Monday!

NOT A LYRID: The Lyrid meteor shower is underway, and peaking this weekend, but this bright fireball photographed Friday night by Chris Peterson of Guffey, Colorado, is not a Lyrid:

Click for video!

"It's just a coincidence that the fireball happened during the Lyrid shower," says Peterson. 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."

"Hundreds of people saw it," he adds. "It was much brighter than the 20% full Moon (magnitude -8.3)." The Moon is the bright spot in the image at azimuth 300 degrees.

Astronomers call this kind of fireball a "sporadic." It was caused by a random fragment of comet or asteroid just happening by on April 20th. The inner solar system is littered with such fragments, and they hit Earth often. Sporadic fireballs as bright as this one appear somewhere on Earth about once a day.

KITE SURFER'S SUN PILLAR: Can you guess, what is the dark crescent in this sunset photo taken yesterday by Mila Zinkova of San Francisco?

"It's a parachute," answers Zinkova. "Surfers use them to ride the waves--a sport called kite surfing. Sometimes the surfers even fly in the air a short distance. I could not show the surfers in the picture, however, because I would have overexposed the sun pillar in the background."

The air, it seems, was filled not only with floating surfers, but also floating ice crystals. Flat plate-shaped crystals fluttering down from high clouds caught the rays of the setting sun and redirected them into a vertical column of light. Sun pillars may be seen whenever icy clouds drift across the sunset. Look for them!

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 22 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

©2013 All rights reserved.