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SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
SPACE WEATHER
Current conditions
Solar wind
speed: 388.5 km/sec
density: 4.4 protons/cm3
explanation | more data
Updated: Today at 2145 UT
X-ray Solar Flares
6-hr max: B1
1735 UT Jan29
24-hr: B1
1735 UT Jan29
explanation | more data
Updated: Today at: 2145 UT
Daily Sun: 29 Jan 08
The sun is blank--no sunspots. Credit: SOHO/MDI
Sunspot number: 0
What is the sunspot number?
Updated 28 Jan 2008
Far side of the Sun:
This holographic image reveals no large sunspots on the far side of the sun. Image credit: SOHO/MDI
Planetary K-index
Now: Kp= 0 quiet
24-hr max: Kp= 2
quiet
explanation | more data
Current Auroral Oval:

Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/POES
Updated:
What is the auroral oval?
Interplanetary Mag. Field
Btotal: 3.2 nT
Bz: 0.8 nT south
explanation | more data
Updated: Today at 2147 UT
Coronal Holes:
A solar wind stream flowing from the indicated coronal hole should reach Earth on or about Jan. 31st. Credit: Hinode X-Ray Telescope.
SPACE WEATHER
NOAA Forecasts
Updated at: 2008 Jan 28 2203 UTC
FLARE
0-24 hr
24-48 hr
CLASS M
01 %
01 %
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: 2008 Jan 28 2203 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
05 %
05 %
MINOR
05 %
05 %
SEVERE
01 %
01 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
10 %
10 %
MINOR
05 %
05 %
SEVERE
02 %
02 %

What's up in Space
January 29, 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.

ASTEROID FLYBY: Asteroid 2007 TU24 is flying past Earth today. There's no danger of a collision, but the 250m-wide space rock is close enough (1.4 lunar distances) to photograph through backyard telescopes as it speeds through the constellation Cassiopeia glowing like a 10th magnitude star. NASA radars are monitoring the flyby and may produce new images of the rock by week's end. [ephemeris] [3D orbit]

KERN ARC: To the casual observer, this photo of ice halos around the sun taken by Marko Mikkilä of Finland may not seem extraordinary, but to experts it is "the halo photo of the decade." The excitement springs from a faint circle around the zenith labeled "Kern arc":

The rare Kern arc completes the circle of the much brighter and frequently seen circumzenithal arc. "Kern arc sightings are few indeed, only two or three reports in the last century, and it has never ever been photographed--until Mikkilä did it last Nov. 17th," says atmospheric optics expert Les Cowley.

"As a diamond dust swarm generated the halo, Mikkilä took dozens of images. The picture above is a stack of 16 images. Astronomers use stacking to reveal faint or elusive details and it does the same for halo displays. However, Mikkilä’s Kern arc was so clear that it is visible on individual images."

"Why is the Kern arc so very rare? The arc has a ray path like that of the circumzenithal arc but with a crucial extra reflection inside flat plate crystals. The contorted path is not possible inside ordinary regular hexagonal plates, instead they have to be almost triangular. Mikkilä sampled and photographed under a microscope the crystals falling around him and lo, many had the required triangular shape."

"The next time you see a bright grin in the sky, look around for the complete circle," urges Cowley. "You might catch a Kern arc of your own."

Note: This photograph was first reported by Tähdet ja avaruus, the Finnish magazine of popular astronomy, in its Jan. 2008 issue.

NACREOUS CLOUDS: As January comes to an end, sky watchers in Scandinavia are recovering from a veritable storm of nacreous clouds. After mid-month, hardly a night went by without someone spotting the phenomenon. "It was incredible! They were all over the sky," says Morton Ross of Oslo, Norway. This picture, taken by Ross on Jan. 25th, shows a typical apparition:

Also known as "Mother of Pearl" clouds, nacreous clouds are peppered with tiny ice crystals that blaze with iridescent color when struck by light from the setting sun. It is these crystals that make nacreous clouds so rare: they require exceptionally low temperatures of minus 85 Celsius (-120 F) to form. Icy nacreous clouds float 9 to 16 miles high, curling and uncurling hypnotically as they are modulated by atmospheric gravity waves.

For much of January, these clouds rolled across the Arctic circle with puzzling regularity. Why the sudden abundance? Is the show over? No one knows. Stay tuned for February!

2008 Nacreous Cloud Gallery
[Night-sky cameras] [Nacreous Basics]

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 January 29, 2008 there were 921 potentially hazardous asteroids.
Jan. 2008 Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Mag.
Size
2005 WJ56
Jan. 10
10.9 LD
11
1.2 km
2008 AF3
Jan. 13
1.0 LD
14
27 m
1685 Toro
Jan. 24
76 LD
13
6.2 km
2007 TU24
Jan. 29
1.4 LD
10
250 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 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, SpaceWeather.com -- This site is penned daily by Dr. Tony Phillips.
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