Solar Wind
speed: 513.8 km/s
3.3 protons/cm3
explanation | more data
Updated: Today at 1537 UT

X-ray Solar Flares

6-hr max:
B1 1145 UT Apr25
24-hr: B6 0705 UT Apr25
explanation | more data
Updated: Today at 1535 UT

Daily Sun: 25 Apr '05

A new sunspot is emerging over the sun's eastern limb. Credit: SOHO/MDI

Sunspot Number: 0
What is the sunspot number?
Updated: 24 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: 2.0 nT
0.6 nT north
explanation | more data
Updated: Today at 1537 UT

Coronal Holes:

A solar wind stream flowing from the indicated coronal hole could reach Earth on April 30th or 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 24 2206 UTC
FLARE 0-24 hr 24-48 hr
CLASS M 05 % 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 2005 Apr 24 2206 UTC
0-24 hr 24-48 hr
ACTIVE 20 % 15 %
MINOR 05 % 05 %
SEVERE 01 % 01 %

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

What's Up in Space -- 25 Apr 2005
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NEW ENGLAND METEOR: New Englanders saw a bright fireball and maybe a whole meteor shower last night (Sunday, April 24th) according to the Associated Press. The origin of the display is still a mystery. Was it late Lyrid activity? Or a piece of decaying space junk? If you witnessed the event, please tell us about it.

SUNSPOT WATCH: Just yesterday the sun was blank, no sunspots, which is a sign that solar minimum is coming. Even during the lowest ebb of the solar cycle, however, spotless periods tend to be brief and, indeed, a new sunspot is already emerging over the sun's eastern limb. It's big (bigger than Earth, at least) but does not pose a threat for very strong solar flares.

LUNAR ECLIPSE: On Sunday morning, April 24th, the full Moon glided through the outer fringes of Earth's shadow, resulting in a "penumbral eclipse." This is what it looked like:

Image credit: Matt Wastell of Brisbane, Australia.

The shadowy darkening across the top of the Moon was, at best, subtle. Onlookers who didn't know an eclipse was in progress might not have noticed. The view from the Moon, on the other hand, was much more dramatic.

STRANGE RAINBOW: That's not an aurora! But it sure did look like one, says Mila Zinkova, who took this picture on April 3rd from the Big Island of Hawaii:

"Mila's telephoto shot has caught a rainbow fragment lighting a distant rain shower scudding over the ocean," explains atmospheric optics Les Cowley. "The 'bow curves low over the water because the sun was fairly high. When the sun is low rainbows are high and they sink lower as the sun climbs. Rainbows do not rise above the horizon when the sun is more than 42 degrees high and so in summer you must catch them within an hour or two of sunrise or sunset."

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 25 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.

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


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