You are viewing the page for Feb. 18, 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: 406.9 km/s
3.6 protons/cm3
explanation | more data
Updated: Today at 2243 UT

X-ray Solar Flares
6-hr max:
B5 1930 UT Feb18
24-hr: B5 1930 UT Feb18
explanation | more data
Updated: Today at 2245 UT

Daily Sun: 18 Feb '07

Sunspot 942 poses no threat for strong solar flares. Credit: SOHO/MDI

Sunspot Number: 11
What is the sunspot number?
Updated: 17 Feb 2007

Far Side of the Sun

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

Interplanetary Mag. Field
Btotal: 3.3 nT
0.9 nT north
explanation | more data
Updated: Today at 2244 UT

Coronal Holes:

Coronal hole data is temporarily unavailable while SOHO's ultraviolet telescope undergoes a CCD bakeout.


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 Feb 18 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 Feb 18 2203 UTC
0-24 hr 24-48 hr
ACTIVE 15 % 15 %
MINOR 10 % 10 %
SEVERE 05 % 05 %

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

What's Up in Space -- 18 Feb 2007
Subscribe to Space Weather News

The space shuttle launches in March. Would you like a call when it soars over your backyard? Spaceweather PHONE!

AURORA MYSTERY MISSION: THEMIS has left the planet. At 6:01 pm EST on Feb. 17th, a Delta rocket carrying five small science satellites blasted off from Kennedy Space Center (KSC). They're on a mission to solve a mystery about the aurora borealis.

"It was a picture-perfect launch," says Mike Theiss at KSC who captured a beautiful sequence of photos: #1, #2, #3, #4, #5.

Photo credit: M. Theiss, Copyright 2007, all rights reserved.

The mystery: Sometimes, with no warning, gently shimmering pale auroras erupt in a riot of wildly-shifting colors. This is called an "auroral substorm" and no one knows what causes it.

THEMIS's five satellites are going to spread out in Earth orbit and observe auroral substorms from above, mapping the storms' magnetic fields. Researchers hope these data will reveal the inner workings of substorms and, in the process, teach us a few new things about Earth's magnetosphere. Stay tuned for updates.

February Aurora Gallery
[aurora alerts] [night-sky cameras]

MIRA VARIABLE: "Last night after sunset, the sky was very clear so I went to a small castle near Stuttgart, the town where I live," says Stefan Seip. "I was surprised to see a new star in the constellation Cetus. Yes, it was Mira!"

Photo details: Canon EOS 1Ds, Canon EF 16-35mm lens, ISO 800, 10 seconds

Mira is a red giant 420 light years from Earth. The entire star expands and contracts every 320 days or so, brightening from invisibility to 2nd magnitude and back again. At its peak--right now--the star is big enough to swallow our entire solar system out to Mars.

Go outside at sunset, face west and take a look. You may be seeing the future. Some astronomers believe the Sun will become a Mira-variable when it evolves to red gianthood five billion years from now. [finder chart]

EXTRA: On Valentine's Day, Pete Lawrence was in Tromso, Norway, and photographed "Mira the Wonderful" shining through the aurora borealis: image. "If you're going to photograph Mira, you might as well do it in style!" he says.

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 18 Feb 2007 there were 843 known Potentially
Hazardous Asteroids

Feb-Mar 2007 Earth-asteroid encounters




2006 AM4

Feb. 1

5.2 LD


180 m
2007 BZ48

Feb. 7

4.5 LD


30 m
2006 VV2

Mar. 31

8.8 LD


2 km
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.