You are viewing the page for Sep. 20, 2004
  Select another date:
<<back forward>>
SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids

SpaceWeather.com
Science news and information about the Sun-Earth environment.

SPACE WEATHER
Current
Conditions

Solar Wind

speed: 372.1 km/s
density:
6.2 protons/cm3
explanation | more data
Updated: Today at 2255 UT

X-ray Solar Flares

6-hr max:
B3 2245 UT Sep20
24-hr: C1 0720 UT Sep20
explanation | more data
Updated: Today at 2245 UT

Daily Sun: 17 Sep '04
Sunspot 673 poses a threat for M-class solar flares. Image credit: SOHO/MDI

The Far Side of the Sun

This holographic image reveals a middling sunspot on the far side of the sun. Image credit: SOHO/MDI


Sunspot Number: 42
What is the sunspot number?
Updated: 19 Sep 2004

Interplanetary Mag. Field
Btotal: 7.1 nT
Bz:
2.5 nT south
explanation | more data
Updated: Today at 2256 UT

Coronal Holes:

The indicated coronal hole might spray a solar wind stream past Earth on Sept 18th or 19th. Image credit: NOAA's Solar X-ray Imager (SXI)


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 2004 Sep 20 2200 UTC
FLARE 0-24 hr 24-48 hr
CLASS M 10 % 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 2004 Sep 20 2200 UTC
Mid-latitudes
0-24 hr 24-48 hr
ACTIVE 20 % 40 %
MINOR 10 % 25 %
SEVERE 01 % 10 %

High latitudes
0-24 hr 24-48 hr
ACTIVE 30 % 50 %
MINOR 15 % 30 %
SEVERE 05 % 15 %

What's Up in Space -- 20 Sep 2004
Subscribe to Space Weather News

Never miss another meteor shower. Or lunar eclipse. Or space station flyby. Sign up for Spaceweather PHONE.

AURORA WATCH: There is a slim (5% to 10%) chance of high-latitude auroras after nightfall on Sept. 21st. The cause: a lopsided coronal mass ejection (CME) might deliver a glancing blow to Earth's magnetic field. The CME was hurled into space by an M1-class explosion near sunspot 672 on Sept. 19th.

CHANGING SEASONS: Northern autumn is the best time of year to see auroras. Why? Scientists aren't sure, but it's true anyway. Northern autumn--and aurora season--begins this year on Sept 22nd at 1630 UT (9:30 a.m. PDT).

Right: Auroras and a meteor over Harstad, Norway, on Sept. 14th. Photo credit: Frank S. Andreassen.

ANALEMMA: If you took a picture of the sun at the same time each day, would it remain in the same position? The answer is no, and the figure-8 shape traced out by the sun over the course of a year is called an analemma.

Greek photographer Anthony Ayiomamitis created this analemma by combining 48 exposures painstakingly collected between March 30, 2003 and March 23, 2004:


Analemma over the Temple of Zeus, Athens, Greece.

Where will the sun be this week when northern autumn begins? "At the mid-way point between the upper and lower extremities of the figure-8," answers Ayiomamitis. [more]



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 20 Sep 2004 there were 618 known Potentially
Hazardous Asteroids

Sept. 2004 Earth-asteroid encounters
ASTEROID

 MISS DISTANCE

 MAG.
2003 UX34

Sept. 9

22 LD

 18
2004 JA27

Sept. 10

23 LD

 19
1998 OX4

Sept. 14

25 LD

 18
Toutatis

Sept. 29

4 LD

 9
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

Editor's Note: This site is sponsored by Science@NASA. Space weather and other forecasts that appear here are formulated by Dr. Tony Phillips. They are not guarantees of space weather or other celestial activity.

You are visitor number 32784507 since January 2000.
©2019 Spaceweather.com. All rights reserved.