You are viewing the page for Feb. 21, 2007
  Select another date:
<<back forward>>
SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids

SpaceWeather.com
Science news and information about the Sun-Earth environment.

SPACE WEATHER
Current
Conditions

Solar Wind
speed: 300.6 km/s
density:
3.5 protons/cm3
explanation | more data
Updated: Today at 2246 UT

X-ray Solar Flares
6-hr max:
A1 1800 UT Feb21
24-hr: A4 0800 UT Feb21
explanation | more data
Updated: Today at 2245 UT

Daily Sun: 20 Feb '07

These sunspots pose no threat for strong solar flares. Credit: SOHO/MDI

Sunspot Number: 27
What is the sunspot number?
Updated: 20 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: 3.7 nT
Bz:
0.7 nT north
explanation | more data
Updated: Today at 2247 UT

Coronal Holes:

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


SPACE WEATHER
NOAA
Forecasts

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 21 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 21 2203 UTC
Mid-latitudes
0-24 hr 24-48 hr
ACTIVE 15 % 15 %
MINOR 10 % 10 %
SEVERE 01 % 01 %

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

What's Up in Space -- 21 Feb 2007
Subscribe to Space Weather News

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

COOL SOLAR MYSTERY: One pole of the sun is cooler than the other. That's the surprising conclusion announced yesterday by scientists who have been analyzing data from the ESA-NASA Ulysses spacecraft: full story.

ROCKET EXPLOSION: Australian astronomer Ray Palmer was photographing the Southern Cross from his observatory in Western Australia on Feb. 19th when a flaming plume cut across the Milky Way. "I had no idea what it was," he says. "It was moving very slowly and I was able to track it for 35 minutes."


Photo details: Nikon FM2, 50mm lens, Kodak Elite Chrome 200, 30 minutes.

In mid-apparition the object exploded. Gordon Garradd of New South Wales photographed an expanding cloud filled with specks of debris. Tim Thorpe of South Australia saw it, too. "Quite a surreal scene," he says.

What was it? It was a mystery for almost 24 hours until satellite expert Daniel Deak matched the trajectory of the plume in Palmer's photo with the orbit of a derelict rocket booster--"a Briz-M, catalog number 28944."

One year ago, the Briz-M sat atop a Russian Proton rocket that left Earth on Feb. 28, 2006, carrying an Arabsat-4A communications satellite. Shortly after launch, the rocket malfunctioned, leaving the satellite in the wrong orbit and the Briz-M looping around Earth partially-filled with fuel. On Feb. 19, 2007, for reasons unknown, the fuel tanks ruptured over Australia.

Jon P. Boers of the USAF Space Surveillance System confirms the ID and notes "later, on the other side of the world, our radar saw 500+ pieces in that orbit." Today the count is up to 1111 fragments. "[We're seeing] more fragments as the cloud expands," he explains.

Some of the fragments are visible in this movie made by Rob McNaught at the Siding Spring Observatory, NSW, Australia:


Photo details: Canon 5D, 50mm lens, f/1.4, 20 x 20sec exposures.

"Spica is at the right edge of the animation and the fragments are moving to the north and east," he says.

One thousand-plus fragments makes this "a major breakup event," says Mark Matney of NASA's Orbital Debris Office at the Johnson Space Center. "There is no immediate threat to the space station, but we're analyzing the orbits to assess any long-term hazard."

"Unlike recent high profile breakups, Briz-M is in an orbit that is difficult for most radars to see," adds Boers. "The generation of element sets on all the pieces will take weeks to accomplish."

Note: Many readers have asked how this event compares to last month's Chinese anti-sat test, which shattered a derelict satellite in low-Earth orbit producing more than 700 catalogued fragments. The Briz-M event could be worse--or not. It depends on the size and distribution of the 1000+ fragments. Ongoing radar studies will provide a better answer in the days and weeks ahead.



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 21 Feb 2007 there were 843 known Potentially
Hazardous Asteroids

Feb-Mar 2007 Earth-asteroid encounters
ASTEROID

 DATE
(UT)

MISS DISTANCE

MAG.

 SIZE
2006 AM4

Feb. 1

5.2 LD

16

180 m
2007 BZ48

Feb. 7

4.5 LD

18

30 m
2006 VV2

Mar. 31

8.8 LD

9

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 lmsal.com.

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 Spaceweather.com. All rights reserved.