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<<back forward>> -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
Current conditions
Solar wind
speed: 508.7 km/sec
density: 1.6 protons/cm3
explanation | more data
Updated: Today at 2246 UT
X-ray Solar Flares
6-hr max: A0
2245 UT Apr18
24-hr: A0
2245 UT Apr18
explanation | more data
Updated: Today at: 2245 UT
Daily Sun: 18 Apr 08
The sun is blank--no sunspots. Credit: SOHO/MDI
Sunspot number: 0
What is the sunspot number?
Updated 18 Apr 2008
Far side of the Sun:
This holographic image reveals no large sunspots on the farside of the sun. Image credit: SOHO/MDI
Planetary K-index
Now: Kp= 1 quiet
24-hr max: Kp= 3
explanation | more data
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
What is the auroral oval?
Interplanetary Mag. Field
Btotal: 3.7 nT
Bz: 2.5 nT north
explanation | more data
Updated: Today at 2247 UT
Coronal Holes:
A solar wind stream flowing from the indicated coronal hole should reach Earth on or about April 24th. Credit: SOHO Extreme UV Telescope
NOAA Forecasts
Updated at: 2008 Apr 18 2203 UTC
0-24 hr
24-48 hr
01 %
01 %
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: 2008 Apr 18 2203 UTC
0-24 hr
24-48 hr
10 %
10 %
05 %
05 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
10 %
10 %
05 %
05 %
01 %
01 %
What's up in Space
April 18, 2008
Where's Saturn? Is that a UFO--or the ISS? What's the name of that star? Get the answers from mySKY--a fun new astronomy helper from Meade.   mySKY

STRANGE HAPPENINGS ON THE MOON: NASA-supported researchers have realized that strange things may be happening on the full Moon when it gets hit by Earth's magnetic tail. Get the full story from Science@NASA.

GREEN RIM: On April 16th, when the sun rose over Borken Germany, it emerged from the horizon green first. Günther Strauch trained his Canon 20D on the verdant edge and took this picture:

Photo details: Vixen refractor, Canon EOS 20D, 100 ASA, 1/1000 second.

What would make the edge of the sun turn green? All that's needed is a giant refracting lens. Earth's atmosphere is such a lens. Density gradients in the lower atmosphere bend light near the horizon, green more so than red: diagram. The green sun rises a little sooner than its red counterpart, hence the green rim.

Green rims require a telescope or zoom lens to see; they are invisible to the unaided eye. Sometimes, however, strong gradients in the atmosphere magnify the green rim to produce a startling green flash, visible, unforgettable, and no telescope required: gallery.

EXTRA: Atmospheric optics expert Les Cowley says there might be a hint of green flash in Strauch's green rim: "The photo shows evidence of some atmospheric temperature layering. The disk is distorted in zones corresponding to large differences in optical extinction and there are also some micro ripples. It is possible therefore that the green has at least some component of a mock-mirage flash."

more images: from Doug Zubenel of Kansas City, Missouri; from Enrique Luque Cervigón of Alcalá de Henares, Madrid, Spain.

BIG SPACESHIP: The International Space Station is growing. In the past six months alone, astronauts have unfurled 230-ft solar wings, added a 30,000-lb docking port (Harmony), installed a 28,000-lb science lab (Columbus) and, while they were at it, a European robot ship (Jules Verne) flew up to the ISS and docked itself. It all adds up to a spaceship so big and bright it fills the eyepiece of a backyard telescope:

Bret Dahl took this picture on April 13th from Plano, Texas. "I used a 10-inch Meade LX200, hand guided," he says. "The ISS has made several nice passes over our area in the last week. In the photo, the space station was about 50 degrees above the horizon. It is amazing how bright the ISS has become even at such a low angle."

A new round of flybys over North American begins in early May. Stay tuned for details.

more images: from Ralf Vandebergh of the Netherlands; from Bill Westphal of Altadena, CA; from Mike Snyder of Cedar Rapids, IA; from Don Lawrence of Sugar Land, Texas; from Robbie Merrill of Fort Collins, CO;

April 2008 Aurora Gallery
[Aurora Alerts] [Night-sky Cameras]

Near-Earth Asteroids
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 is on a collision course with our planet, although astronomers are finding new ones all the time. [comment]
On April 18, 2008 there were 947 potentially hazardous asteroids.
April 2008 Earth-asteroid encounters:
Miss Distance
2008 FH5
Apr. 2
7.6 LD
17 m
2001 QO142
Apr. 6
34 LD
685 m
2008 GF1
Apr. 7
0.8 LD
10 m
2005 BE2
Apr. 10
62 LD
1.0 km
2005 NB7
Apr. 17
16 LD
705 m
2008 FU6
Apr. 22
62 LD
1.4 km
2005 TB
Apr. 28
47 LD
1.3 km
2001 DQ8
Apr. 30
74 LD
1.1 km
Notes: LD means "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 Links
NOAA Space Weather Prediction 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.
Solar and Heliospheric Observatory
  Realtime and archival images of the Sun from SOHO.
Daily Sunspot Summaries
  From the NOAA Space Environment Center
Current Solar Images
  from the National Solar Data Analysis Center
  more links...
©2008, -- This site is penned daily by Dr. Tony Phillips.
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