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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

velocity: 381.0 km/s
37.3 protons/cm3
explanation | more data
Updated: Today at 2245 UT

X-ray Solar Flares

6-hr max:
C3 2245 UT Apr21
24-hr: C4 0445 UT Apr21
explanation | more data
Updated: Today at 2250 UT

Daily Sun: 21 Apr '01
Sunspot 9435 is growing rapidly and could soon pose a threat for substantial flares. The returning sunspot 9393 (also known as 9433) has a twisted beta-gamma magnetic field that likely harbors energy for strong M-class flares.

Sunspot Number: 103
More about sunspots
Updated: 20 Apr 2001

Radio Meteor Rate
24 hr max:
117 per hr
Listen to the Meteor Radar!
Updated: 20 Apr 2001

Interplanetary Mag. Field
Btotal: 5.8 nT
5.0 nT north
explanation | more data
Updated: Today at 2248 UT

Coronal Holes:

There are no substantial coronal holes revealed in this soft x-ray image of the Sun. Image credit: Yohkoh Soft X-ray Telescope.
More about coronal holes


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 2001 Apr 21 2200 UT

FLARE 24 hr 48 hr
CLASS M 75 % 75 %
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 2001 Apr 21 2200 UT

24 hr 48 hr
ACTIVE 20 % 20 %
MINOR 10 % 10 %
SEVERE 01 % 01 %

High latitudes
24 hr 48 hr
ACTIVE 20 % 20 %
MINOR 10 % 10 %
SEVERE 01 % 01 %

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What's Up in Space -- 21 Apr 2001
Subscribe to Space Weather News!

LYRID METEORS: The Lyrid meteor shower peaks on Sunday April 22nd. If clouds threaten to spoil the show where you live, you can listen to the Lyrids by tuning in to the NASA meteor radar at the Marshall Space Flight Center. [listen!]

IT'S BACK: Giant sunspot 9393 -- the source of the biggest solar flare ever recorded and several geomagnetic storms earlier this month-- disappeared two weeks ago when it rotated around the Sun's western limb. Now, after crossing the back side of our star, 9393 has returned. At its peak on March 28th the active region covered an area equal to fourteen planet Earths. The behemoth is now only a shadow of its former self, covering an area of five Earths on April 20th.

Above: This SOHO white light image of the Sun reveals sunspot 9393 returning over the Sun's eastern limb.

NEW AURORA IMAGES: As night fell across North America last Tuesday an interplanetary shock wave swept past Earth and triggered a strong G3-category geomagnetic storm. Sky watchers across Canada and in many US states (as far south as California) spotted bright Northern Lights. If you missed the storm, don't worry, you can still visit our April 18th 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. [more]

On 21 Apr 2001 there were 304 known Potentially
Hazardous Asteroids

April 2001 Earth-asteroid encounters


 Date (UTC)

 Miss Distance
2001 GT2  2001-Apr-01 00:09

 0.0454 AU
2001 HB  2001-Apr-02 04:21

 0.0323 AU
2001 FA58  2001-Apr-02 07:56

 0.1128 AU
1986 PA  2001-Apr-03 01:06

 0.1465 AU
2000 EE104  2001-Apr-12 20:37

 0.0822 AU
2001 GR2  2001-Apr-18 04:07

 0.0761 AU
2001 GQ2  2001-Apr-27 12:00

 0.0199 AU

  • TOTAL LUNAR ECLIPSE: On Jan. 9, 2001, the full Moon glided through Earth's copper-colored shadow. [gallery]
  • CHRISTMAS ECLIPSE: Sky watchers across North America enjoyed a partial solar eclipse on Christmas Day 2000 [gallery]
  • LEONIDS 2000: Observers around the globe enjoyed three predicted episodes of shooting stars. [gallery]

Feb. 21, 2001: Nature's Tiniest Space Junk -- Using an experimental radar at the Marshall Space Flight Center, scientists are monitoring tiny but hazardous meteoroids that swarm around our planet.

Feb. 15, 2001: The Sun Does a Flip -- NASA scientists who monitor the Sun say our star's enormous magnetic field is reversing -- a sure sign that solar maximum is here.

Jan. 25, 2001: Earth's Invisible Magnetic Tail -- NASA's IMAGE spacecraft, the first to enjoy a global view of the magnetosphere, spotted a curious plasma tail pointing from Earth toward the Sun.

Jan. 4, 2001: Earth at Perihelion -- On January 4, 2001, our planet made its annual closest approach to the Sun.

Dec. 29, 2000: Millennium Meteors -- North Americans will have a front-row seat for a brief but powerful meteor shower on January 3, 2001.

Dec. 28, 2000: Galileo Looks for Auroras on Ganymede -- NASA's durable Galileo spacecraft flew above the solar system's largest moon this morning in search of extraterrestrial "Northern Lights"

Dec. 22, 2000: Watching the Angry Sun -- Solar physicists are enjoying their best-ever look at a Solar Maximum thanks to NOAA and NASA satellites.







Editor's Note: Space weather forecasts that appear on this site are based in part on data from NASA and NOAA satellites and ground-monitoring stations. Predictions and explanations are formulated by Dr. Tony Phillips; they are not official statements of any government organ or guarantees of space weather activity.

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.

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.

The Latest SOHO Coronagraph Images -- from the Naval Research Lab

The Latest Space Weather Values -- from the NOAA Space Environment Center.

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.

Real-time Solar Wind Data -- from NASA's ACE spacecraft.

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.

NOAA geomagnetic latitude maps: North America, Eurasia, South Africa & Australia, South America

Quarterly Solar Flare and Sunspot Data: January - March 2000 -- from the NOAA Space Environment Center.

Quarterly Solar Flare and Sunspot Data: April - June 2000 -- from the NOAA Space Environment Center.

Quarterly Solar Flare and Sunspot Data: July - Sept 2000 -- from the NOAA Space Environment Center.

Quarterly Solar Flare and Sunspot Data: Oct. - Dec. 2000 -- from the NOAA Space Environment Center.

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