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<<back forward>> -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
Current conditions
Solar wind
speed: 465.7 km/sec
density: 0.5 protons/cm3
explanation | more data
Updated: Today at 2345 UT
X-ray Solar Flares
6-hr max: A0
2340 UT Sep17
24-hr: A0
2340 UT Sep17
explanation | more data
Updated: Today at: 2340 UT
Daily Sun: 17 Sept. 09
The Earth-facing side of the sun is blank--no sunspots.. Photo credit: SOHO/MDI
Sunspot number: 0
What is the sunspot number?
Updated 15 Sept 2009

Spotless Days
Current Stretch: 14 days
2009 total: 207 days (81%)
Since 2004: 718 days
Typical Solar Min: 485 days
explanation | more info
Updated 15 Sept 2009

Far side of the Sun:
This holographic image reveals a growing active region on the far side of the sun. It is located at latitude 30-deg south, making it a probable member of Solar Cycle 24. Image credit: Global Oscillation Network Group
Planetary K-index
Now: Kp= 2 quiet
24-hr max: Kp= 3
explanation | more data
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Interplanetary Mag. Field
Btotal: 3.8 nT
Bz: 1 nT south
explanation | more data
Updated: Today at 2346 UT
Coronal Holes:
A solar wind stream flowing from the indicated coronal hole could reach Earth as early as Sept. 17th. Credit: SOHO Extreme UV Telescope
NOAA Forecasts
Updated at: 2009 Sep 17 2201 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: 2009 Sep 17 2201 UTC
0-24 hr
24-48 hr
05 %
05 %
01 %
01 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
05 %
05 %
01 %
01 %
01 %
01 %
What's up in Space
September 17, 2009

AURORA ALERT: Did you miss the Northern Lights? Next time get a wake-up call: Spaceweather PHONE.


CONVERGING SPACESHIPS: Japan's HTV-1 cargo carrier is approaching the International Space Station (ISS) for docking on Thursday, Sept. 17th. The docking procedure, which requires the station's robotic arm to reach out and grab the HTV-1, begins at 3:50 pm EDT. HTV-1 is as bright as a first-magnitude star, so it should be easy to see beside the much larger ISS. Check the Simple Satellite Tracker for flybys.

NORTHERN LIGHTS: The long, bright Arctic summer is coming to an end, and that means it's time to watch out for Northern Lights. On Sept. 15th, photographer Bud Kuenzli caught these auroras arcing over North Pole, Alaska:

The display was sparked by a mild gust of solar wind. At this time of year, a mild gust is all it takes. The weeks around equinoxes are prime time for Northern Lights. As summer turns into autumn, the interplanetary magnetic field (IMF) near Earth tends to tilt south, an orientation that weakens our planet's magnetic defenses against the solar wind. The slightest gust can produce a lovely show.

Polar sky watchers should be alert for auroras in the weeks ahead.

UPDATED: Sept. 2009 Aurora Gallery
[previous Septembers: 2008, 2007, 2006, 2005, 2004, 2002, 2001]

AUTUMN SUNRISE: Morning fog is a sign of autumn. The weeks of late September and early October often bring banks of fog to the countryside, where moist ground has spent the lengthening night cooling under a cloudless, starry sky. The combination of cool air and low fog can produce some interesting vistas:

Mike Hollingshead of Blair, Nebraska, took the picture at daybreak on Sept. 16th. "A few mornings ago, I noticed how red the sun appeared when it rose through the fog," he says. "I wanted more--and yesterday I got it." The sun was not only reddened but also miraged by a temperature inversion in the air above the chilly field.

"These foggy mornings produce some nice photo-ops," he says. "You just need a bit of a hill to shoot from to see the mirage, but not too high because you want to shoot through the fog to get the vibrant red stuff."

Photographers, set your alarm for sunrise. And hurry. The fog won't wait forever.

Explore the Sunspot Cycle

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.
On September 17, 2009 there were 1070 potentially hazardous asteroids.
Sept. 2009 Earth-asteroid encounters:
Miss Distance
2009 QC35
Sept. 2
2.9 LD
35 m
2009 HD21
Sept. 29
22.9 LD
1.0 km
1998 FW4
Sept. 29
8.6 LD
550 m
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 space weather bureau
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.
  3D views of the sun from NASA's Solar and Terrestrial Relations Observatory
Daily Sunspot Summaries
  from the NOAA Space Environment Center
Current Solar Images
  from the National Solar Data Analysis Center
Science Central
  more links...
©2008, -- This site is penned daily by Dr. Tony Phillips.
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