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SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids

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Science news and information about the Sun-Earth environment.

SPACE WEATHER
Current
Conditions

Solar Wind
speed: 344.9 km/s
density:
13.1 protons/cm3
explanation | more data
Updated: Today at 2255 UT


X-ray Solar Flares

6-hr max:
A1 2020 UT Oct21
24-hr: B2 0450 UT Oct21
explanation | more data
Updated: Today at 2245 UT

Daily Sun: 21 Oct '05

Decaying sunspot 815 poses no threat for strong solar flares. Solar activity should remain low. Credit: SOHO/MDI


Sunspot Number: 15
What is the sunspot number?
Updated: 20 Oct 2005

Far Side of the Sun

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

Interplanetary Mag. Field
Btotal: 7.6 nT
Bz:
6.5 nT south
explanation | more data
Updated: Today at 2256 UT

Coronal Holes:

A solar wind stream flowing from the indicated coronal hole might reach Earth on Oct. 23rd or 24th. Image credit: SOHO Extreme UV Telescope.


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 2005 Oct 20 2204 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 2005 Oct 20 2204 UTC
Mid-latitudes
0-24 hr 24-48 hr
ACTIVE 15 % 20 %
MINOR 10 % 15 %
SEVERE 01 % 05 %

High latitudes
0-24 hr 24-48 hr
ACTIVE 15 % 25 %
MINOR 10 % 20 %
SEVERE 01 % 10 %

What's Up in Space -- 21 Oct 2005
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QUIET SUN: Solar activity continues to be very low. Flares and auroras are unlikely this week.

GREEN MARS: There's a huge dust storm sweeping across Mars, big enough to see through backyard telescopes. Amateur astronomers have been monitoring it for days. Last night, Joel Warren of Amarillo, Texas, was photographing the storm when he noticed something odd: Mars is turning green. (continued below)

"Yellow dust clouds are mixing with [icy-blue] morning clouds to create greenish clouds," he explains. Warren is an experienced nightly photographer of Mars. "I'm quite sure [about the green color]," he says.

Dust storms are an important form of Martian weather. Sometimes they grow to envelop the whole planet! What will this storm do next? Stay tuned.

more images: from Alan Friedman of Buffalo, New York; from Bill Dickinson of Glen Allen, Virginia; from Joel Warren of Amarillo, Texas; from Ed Grafton of Houston, Texas; from Larry Owens of Atlanta, Georgia.

GREEN FLASH: Sometimes when the sun is setting over the ocean, and it is just about to vanish beneath the waves, observers see a surprising flash of emerald green. "I had been trying to capture the elusive green flash on many vacations to the Big Island of Hawaii," says Steve Cullen. "I was finally rewarded this week with a complete 10-frame sequence showing the flash from start to finish--which was less than 5 seconds." To see the movie, click on the image below:

"This is a classical green flash," comments atmospheric optics expert Les Cowley. "Most websites and books say it is made when the atmosphere bends green and red rays differently, but that effect is much too small. We need something extra to magnify it and a mirage does that. A layer of warm air next to the ocean produced the magnifying mirage for this flash. Different mirage conditions make several other types of green flash - how many can you collect?"



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 are on a collision course with our planet, although astronomers are finding new ones all the time.

On 21 Oct 2005 there were 710 known Potentially
Hazardous Asteroids

August 2005 Earth-asteroid encounters
ASTEROID

 DATE (UT)

 MISS DISTANCE

 MAG.
1992 UY4

August 8

16 LD

 12
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. See also Snow Crystals.

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 --a gallery of up-to-date solar pictures from the National Solar Data Analysis Center at the Goddard Space Flight Center. See also the GOES-12 Solar X-ray Imager.

Recent Solar Events -- a nice summary of current solar conditions from lmsal.com.

SOHO Farside Images of the Sun from SWAN and MDI.

The Latest SOHO Coronagraph Images -- from the Naval Research Lab

The Sun from Earth -- daily images of our star from the Big Bear Solar Observatory

List of Potentially Hazardous Asteroids -- from the Harvard Minor Planet Center.

Observable Comets -- from the Harvard Minor Planet Center.

What is the Interplanetary Magnetic Field? -- A lucid answer from the University of Michigan. See also the Anatomy of Earth's Magnetosphere.

Real-time Solar Wind Data -- from NASA's ACE spacecraft. How powerful are solar wind gusts? Read this story from Science@NASA.

More Real-time Solar Wind Data -- from the Solar and Heliospheric Observatory Proton Monitor.

Aurora Forecast --from the University of Alaska's Geophysical Institute

Daily Solar Flare and Sunspot Data -- from the NOAA Space Environment Center.

Lists of Coronal Mass Ejections -- from 1998 to 2001

What is an Iridium flare? See also Photographing Satellites by Brian Webb.

What is an Astronomical Unit, or AU?

Mirages: Mirages in Finland; An Introduction to Mirages;

NOAA Solar Flare and Sunspot Data: 1999; 2000; 2001; 2002; 2003; 2004; Jan-Mar., 2005;

Space Audio Streams: (University of Florida) 20 MHz radio emissions from Jupiter: #1, #2, #3, #4; (NASA/Marshall) INSPIRE: #1; (Stan Nelson of Roswell, New Mexico) meteor radar: #1, #2;

Recent International Astronomical Union Circulars

GLOSSARY | SPACE WEATHER TUTORIAL

This site is penned daily by Dr. Tony Phillips: email

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