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Science news and information about the Sun-Earth environment.

SPACE WEATHER
Current
Conditions

Solar Wind
speed: 438.3 km/s
density:
4.1 protons/cm3
explanation | more data
Updated: Today at 2246 UT

X-ray Solar Flares

6-hr max:
B7 2100 UT Feb17
24-hr: C1 0000 UT Feb17
explanation | more data
Updated: Today at 2245 UT

Daily Sun: 17 Feb '05

Sunspot 735 poses a threat for M-class solar flares. . Credit: SOHO/MDI


Sunspot Number: 61
What is the sunspot number?
Updated: 16 Feb 2005

Far Side of the Sun

This holographic image reveals one small sunspot group on the far side of the Sun. Image credit: SOHO/MDI

Interplanetary Mag. Field
Btotal: 14.3 nT
Bz:
8.8 nT south
explanation | more data
Updated: Today at 2246 UT

Coronal Holes:

A solar wind gust flowing from the indicated coronal hole could hit Earth's magnetic field on Feb. 18th. 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 Feb 17 2200 UTC
FLARE 0-24 hr 24-48 hr
CLASS M 15 % 15 %
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 Feb 17 2200 UTC
Mid-latitudes
0-24 hr 24-48 hr
ACTIVE 25 % 30 %
MINOR 25 % 25 %
SEVERE 05 % 05 %

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

What's Up in Space -- 17 Feb 2005
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AURORA WATCH: Later today or tomorrow, Earth will pass through a solar wind stream spewing from a coronal hole on the sun. Sky watchers in Alaska, Canada and Scandinavia should be alert for auroras.

SUNSPOTS: Magnetic fields around sunspot 735 have been twisting, stretching and growing more complicated since the beginning of the week. If the trend continues, there could be a magnetic eruption--in other words, a solar flare. NOAA forecasters estimate a 15% chance of an M-class flare during the next 24 hours.

In Rockville, Maryland, on February 16th, Greg Piepol took this picture of the sun. Sunspot 735 is in the middle pointing directly at Earth:

more images: from Gary Palmer of Los Angeles, CA; from Laurent Laveder of Quimper, Bretagne, France; from Eric von der Heyden of Darmstadt, Germany; from Didier Favre of Los Angeles, CA, USA [more]

HAPPY BIRTHDAY, GALILEO: On February 15, 1564, Galileo Galilei was born in Pisa, Italy. If he were alive today he would be 441 years old. Galileo is an important person in the history of space weather. Contrary to popular belief, he didn't discover sunspots, but he was one of the first to observe them using a telescope.

In Galileo's day, many people believed sunspots were satellites of the sun. Galileo proved otherwise. By drawing sunspots every day, he discovered that the sun spins and that sunspots are located on (or very near) the sun's surface. Galileo thought sunspots might be clouds.

Right: Sunspots drawn by Galileo in June 1612. [more drawings]

Now we know what sunspots really are: magnetic islands. Sunspots consist of magnetic force-fields poking through the sun's surface from below. Sometimes these magnetic fields erupt, producing a solar flare. With a temperature of "only" a few thousand degrees C, sunspots are cooler than their surroundings and, thus, they appear dark. Sunspots are as big as planets.

Do-it-yourself Sunspot Observing Tips



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 17 Feb 2005 there were 662 known Potentially
Hazardous Asteroids

Jan.-Feb. 2005 Earth-asteroid encounters
ASTEROID

 MISS DISTANCE

 MAG.
1998 DV9

Jan. 11

30 LD

 15
2004 EW

Feb. 14

23 LD

 16
2004 RF84

Feb. 27

23 LD

 14
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.

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

GLOSSARY | SPACE WEATHER TUTORIAL

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

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