Solar Wind
speed: 605.7 km/s
3.2 protons/cm3
explanation | more data
Updated: Today at 1855 UT

X-ray Solar Flares

6-hr max:
B3 1715 UT Sep04
24-hr: B3 1715 UT Sep04
explanation | more data
Updated: Today at 1845 UT

Daily Sun: 04 Sep '06

The sun is blank today--no sunspots. Credit:

Sunspot Number: 0
What is the sunspot number?
Updated: 03 Sep 2006

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: 6.0 nT
2.4 nT north
explanation | more data
Updated: Today at 1856 UT

Coronal Holes:

Earth is inside a solar wind stream flowing from the indicated coronal hole. Credit: NOAA GOES-13.


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 2006 Sep 03 2203 UTC
FLARE 0-24 hr 24-48 hr
CLASS M 01 % 05 %
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 2006 Sep 03 2203 UTC
0-24 hr 24-48 hr
ACTIVE 20 % 15 %
MINOR 10 % 05 %
SEVERE 01 % 01 %

High latitudes
0-24 hr 24-48 hr
ACTIVE 25 % 20 %
MINOR 15 % 10 %
SEVERE 05 % 01 %

What's Up in Space -- 4 Sep 2006
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Did you miss the aurora surprise of August? Next time get a wake-up call: Spaceweather PHONE.

LUNAR FLASH: Exactly as planned, Europe's SMART-1 spacecraft crashed into the Moon on Sept. 3rd at 0542 UT. The resulting flash was too faint for most backyard telescopes, but a team of astronomers using the big 3.6-meter CFH telescope in Hawaii did photograph the explosion:

Credit: Canada-France-Hawaii Telescope / 2006 [More images]

The flash in this animation is an infrared flash. It shows heat generated by the spacecraft's 4500 mph impact into the lunar surface near the edge of Lacus Excellentiae (34.4 S, 46.2 W).

Lacus Excellentiae was in darkness when SMART-1 hit--the better to see the flash. Today, however, the sun is rising and illuminating the impact site. Amateur and professional astronomers will scour the area for additional signs of the crash. [ESA press release]

BRIGHT AURORAS: Last night, photographer Geoff Lussier of Manitoba, Canada, "had a feeling" he should stay up late--and he was right. Around 2:30 in the morning, the sky over Patrica Beach (where he had his camera set up) erupted in color:

September 2006 Aurora Gallery

The display was caused by a solar wind stream hitting Earth's magnetic field. It was a gentle gust, but at this time of year even gentle gusts can cause bright Northern Lights. What's special about "this time of year"? Auroras appear more often during the early months of autumn than at any other time of year. It's aurora season, so be prepared!

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 4 Sep 2006 there were 803 known Potentially
Hazardous Asteroids

Aug-Sept 2006 Earth-asteroid encounters




2006 QM111

Aug 31

0.4 LD


13 m
2006 QQ56

Sept. 2

7.9 LD


29 m
2006 QV89

Sept. 5

7.9 LD


40 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. 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

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.

Lists of Coronal Mass Ejections -- from 1998 to 2001

Mirages: Mirages in Finland; An Introduction to Mirages;

NOAA Solar Flare and Sunspot Data: 1996, 1997, 1998, 1999; 2000; 2001; 2002; 2003; 2004; 2005; Jan-Mar 2006;

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


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

40 m
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