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<<back forward>> -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
Science news and information about the Sun-Earth environment.


Solar Wind
speed: 392.3 km/s
14.3 protons/cm3
explanation | more data
Updated: Today at 2246 UT

X-ray Solar Flares

6-hr max:
C1 2040 UT Apr29
24-hr: C1 2040 UT Apr29
explanation | more data
Updated: Today at 2245 UT

Daily Sun: 29 Apr '05

Sunspot 756 poses a threat for M-class solar flares. Credit: SOHO/MDI

Sunspot Number: 71
What is the sunspot number?
Updated: 28 Apr 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: 9.4 nT
0.7 nT north
explanation | more data
Updated: Today at 2246 UT

Coronal Holes:

A solar wind stream flowing from the indicated coronal hole could reach Earth on May 1st. Image credit: SOHO Extreme Ultraviolet 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 2005 Apr 28 2208 UTC
FLARE 0-24 hr 24-48 hr
CLASS M 30 % 30 %
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 Apr 28 2208 UTC
0-24 hr 24-48 hr
ACTIVE 10 % 10 %
MINOR 01 % 01 %
SEVERE 01 % 01 %

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

What's Up in Space -- 29 Apr 2005
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MAY AURORAS: Sky watchers in Alaska and Canada should be alert for auroras on May 1st and 2nd. That's when Earth is expected to run into a solar wind stream flowing from a coronal hole on the sun.

BIG SUNSPOT: Since it appeared on April 25th, sunspot 756 has tripled in size. It's now about five times wider than Earth and very dynamic. SOHO images show the 'spot changing shape hourly:

A 3-day SOHO animation of sunspot 756.

Sunspot 756 is a fine sight through properly-filtered telescopes. If you don't have one of those, try building a simple solar projector: it's easy.

Using an "H-alpha" filter tuned to the red glow of solar hydrogen, Didier Favre of Los Angeles, CA, snapped this picture of sunspot 756 on April 26th when it was only twice the size of Earth:

more images: from Jörgen Blom of Stockholm, Sweden; from Jérôme Grenier of Paris, France; from Pavol Rapavy of Rimavska Sobota, Slovakia; from Ron Wayman of Tampa, Florida; from Gary Palmer of Los Angeles, CA; from Peter Paice of Belfast, Northern Ireland; from Sylvain Weiller of St Rémy les Chevreuse, France.

RAINBOWS IN THE NIGHT: It was a dark and stormy night in Great Falls, Montana, around 2 o'clock in the morning on April 27th when Jonathan Logan snapped these two pictures 20 seconds apart:

Notice anything strange? It's the rainbow. Rainbows are made of raindrops and sunlight, but at 2 o'clock in the morning there is no sunlight. The solution: this is a lunar rainbow. Behind the photographer's back, a nearly-full Moon was shining brightly. Moonbeams illuminated raindrops beneath the crackling thunderhead, forming a rare and beautiful rainbow in the night.

BONUS: April 24th Lunar Eclipse 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 29 Apr 2005 there were 681 known Potentially
Hazardous Asteroids

April 2005 Earth-asteroid encounters



2005 EU2

Apr. 5

6.2 LD

2005 EE169

Apr. 6

5.9 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.

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


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

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