Solar Wind

speed: 490.1 km/s
0.5 protons/cm3
explanation | more data
Updated: Today at 1915 UT

X-ray Solar Flares

6-hr max:
C6 1620 UT Aug12
24-hr: M1 0505 UT Aug12
explanation | more data
Updated: Today at 1915 UT

Daily Sun: 12 Aug '04
Sunspot 649 has a "beta-gamma-delta" magnetic field that harbors energy for X-class solar flares. Image credit: SOHO/MDI

The Far Side of the Sun

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

Sunspot Number: 115
What is the sunspot number?
Updated: 11 Aug 2004

Interplanetary Mag. Field
Btotal: 3.5 nT
2 nT south
explanation | more data
Updated: Today at 1917 UT

Coronal Holes:

Earth is inside a solar wind stream flowing from the indicated loosely-organized coronal hole. Image 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 2004 Aug 11 2200 UTC
FLARE 0-24 hr 24-48 hr
CLASS M 55 % 55 %
CLASS X 10 % 10 %

Geomagnetic Storms: Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm
Updated at 2004 Aug 11 2200 UTC
0-24 hr 24-48 hr
ACTIVE 30 % 30 %
MINOR 15 % 15 %
SEVERE 05 % 05 %

High latitudes
0-24 hr 24-48 hr
ACTIVE 35 % 35 %
MINOR 15 % 15 %
SEVERE 05 % 05 %

What's Up in Space -- 12 Aug 2004
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PERSEID METEORS: The peak of the Perseid meteor shower has come and gone, but the shower isn't done yet. Earth is still inside the dusty tail of Comet Swift-Tuttle. Sky watchers who go outside tonight--after midnight is best--could see a dozen or so meteors per hour. Reminder: Avoid city lights. Dark skies reveal more meteors.

At the Observatory Hoefingen near Stuttgart, Germany, Stefan Seip photographed this Perseid fireball on August 12th. "It was green," says Seip, "and about three times brighter than Venus."

Click on the image to view the fireball plus two more Perseids streaking along the Milky Way.

Got clouds? Try listening to the Perseids:

When a Perseid flies over one of these meteor radars, they record a ghostly ping. Credit: Live audio provided by engineer Stan Nelson.

BIG SUNSPOT: Sunspot 649 is simply enormous. You can see it without a telescope, but never stare at the blinding sun. Instead, use a sun-safe filter or build a build a solar projector. It's easy!

Enrico Perissinotto of Premariacco, Italy, took this picture of the giant active region on August 11th. Note how complicated the sunspot looks. It has an equally complicated magnetic field that harbors energy for powerful X-class solar flares.

more images: from Mike Sierra of Anchorage, Alaska; from Bruno Nolf of Otegem, Belgium; from Peter Paice of Belfast, Northern Ireland; from Jack Newton of Arizona;

August 2004 Aurora Gallery

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 12 Aug 2004 there were 618 known Potentially
Hazardous Asteroids
July-Sept. 2004 Earth-asteroid encounters



1999 MN

July 11

8 LD

2001 OY13

July 14

25 LD

2000 PH5

July 25

5 LD

2003 UX34

Sept. 9

22 LD

2004 JA27

Sept. 10

23 LD

1998 OX4

Sept. 14

25 LD


Sept. 29

4 LD

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

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.

Vandenberg AFB missile launch schedule.

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; Jan-Mar., 2004;

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


Editor's Note: This site is sponsored by Science@NASA. Space weather and other forecasts that appear here are formulated by Dr. Tony Phillips. They are not guarantees of space weather or other celestial activity.
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