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<<back forward>> -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
Solar wind
speed: 319.4 km/sec
density: 1.7 protons/cm3
explanation | more data
Updated: Today at 2344 UT
X-ray Solar Flares
6-hr max: B2
1735 UT Feb03
24-hr: B2
0556 UT Feb03
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 03 Feb 11
Sunspot 1150 is in a state of decay. Strong flares are unlikely. Credit: SDO/HMI
Sunspot number: 22
What is the sunspot number?
Updated 02 Feb 2011

Spotless Days
Current Stretch: 0 days
2011 total: 1 day (3%)
2010 total: 51 days (14%)
2009 total: 260 days (71%)
Since 2004: 820 days
Typical Solar Min: 486 days

Updated 02 Feb 2011

The Radio Sun
10.7 cm flux: 79 sfu
explanation | more data
Updated 02 Feb 2011

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Planetary K-index
Now: Kp= 0 quiet
24-hr max: Kp= 1
explanation | more data
Interplanetary Mag. Field
Btotal: 2.1 nT
Bz: 0.1 nT north
explanation | more data
Updated: Today at 2345 UT
Coronal Holes: 03 Feb 10
A solar wind stream flowing from the indicated coronal hole should reach Earth on Feb. 3rd or (more likely) the 4th. Credit: SDO/AIA.
NOAA Forecasts
Updated at: 2011 Feb 03 2200 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: 2011 Feb 03 2200 UTC
0-24 hr
24-48 hr
30 %
25 %
40 %
10 %
10 %
05 %
High latitudes
0-24 hr
24-48 hr
40 %
30 %
45 %
20 %
15 %
10 %
Thursday, Feb. 3, 2011
What's up in space

Metallic photos of the sun by renowned photographer Greg Piepol bring together the best of art and science. Buy one or a whole set. They make a stellar gift.

Metallic pictures of the Sun

GEOMAGNETIC STORM WATCH: NOAA forecasters estimate a 60% chance of polar geomagnetic storms on Feb. 3rd when a coronal mass ejection is due to hit Earth's magnetic field. A solar wind stream following close behind the CME could extend the action into Feb. 4th and 5th. High-latitude sky watchers should be alert for auroras.

SOLAR SAIL FLARES: NASA's new solar sail, NanoSail-D, is circling Earth and attracting the attention of sky watchers--especially when it flares. Sunlight glinting off the sail's reflective fabric can rival the brightest stars, making a sudden and luminous streak across the night sky. Here it is over Rautalampi, Finland, on Jan. 30th:

Photo details: Nikon D70s, 18 mm/f/3.5, ISO 1600, 30 sec exposures

"At its peak, the flare was magnitude +3.5, easily seen with the naked eye," says photographer Vesa Vauhkonen. "I was able to photograph the event using an ordinary digital camera (a Nikon D70s)."

On the same night, NanoSail-D flared even more brightly over Helsinki, Finland. A meteor camera operated by Esko Lyytinen caught the sail flashing almost three times brighter than a 1st magnitude star: image.

Future flares could dwarf these. NanoSail-D is skimming the top of Earth's atmosphere and slowly descending as it circles the planet. As the spacecraft gets closer to Earth and aerodynamic forces flatten the fabric into an ever-better reflector, flares are likely to intensify, theoretically exceeding the brightness of Venus as much as 100-fold (5 magnitudes). Photograph one of those and you just might win $500.

more images: from Enzo De Bernardini of Buenos Aires, Argentina; from Arto Oksanen of Jyväskylä, Finland; from Mika Järvinen of Finland

SNOW SPIRALS--READER FEEDBACK: Regarding the snow spirals, described below, many readers have offered explanations for the phenomenon. Scroll to the bottom of the article for a summary.

SNOW SPIRALS: As a winter storm of historic proportions sweeps across the central USA this week, midwesterners should be alert for some unaccustomed sights. One of them is snow spirals. Michael French photographed this specimen in Frederick, Maryland, on Jan. 29th:

"I call them Karra Spirals, after my wife Karra Strickland who discovered them in our yard," says French. "They were all over town, spiraling down the braided metal guy-wires on telephone poles. Here's the curious thing: The wires were spun clockwise, while the snow formations were spun anti-clockwise. The hardened snow spirals were rotated opposite of the metal wire's weave. We also noticed that spirals near the top of the wires were longer (~1 meter) than spirals at the bottom (0.1 - 0.3 meters)--perhaps because of gravity?"

Indeed, the changing wavelength of the spiral suggests gravity played a role in their formation. This could be how heavy snow sags under its own weight when it clings to a braided wire. Why the spirals should oppose the braid, however, is not obvious. Readers with explanations are invited to submit them for consideration.

READER FEEDBACK (CONTINUED): A popular suggestion was that Coriolis forces twisted the snow around the wire. This cannot be correct because the scale of the phenomenon is too small for a significant Coriolis effect. Likewise, water swirling down the drain of your shower is not guided by the Coriolis force; hurricanes, however, are.

Many readers noticed that the swirl of the snow was perpendicular to the underlying braid of the wire. This observation led to the most elegant explanation: "As the snow slides down, it will follow the twist of the wire, hence the spiral builds up with the opposite twist," said reader Jim Easterbrook. Another reader, Uwe Heine, added that "snow sliding down compresses the snow ahead of it. As the spirals 'pile up' the 'wavelength' of the spirals gets shorter, hence the shorter spirals near the ground." Many correspondents echoed these ideas.

Other ideas involving wind and the circular vibration of the guy wire had merit, too, but we will give the last word to reader Matt Kolasinski: "I think it was a bunch of snow sprites having some fun, building their own version of a luge run." Case closed.

January 2011 Aurora Photo Gallery
[previous Januaries: 2010, 2009, 2008, 2007, 2005, 2004]

  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 February 3, 2011 there were 1191 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Miss Distance
2011 AL37
Jan 26
2.2 LD
60 m
2011 BF10
Jan 30
9.1 LD
14 m
2011 BG24
Jan 30
5.9 LD
23 m
2011 BE24
Feb 3
9.3 LD
35 m
2003 YG118
Feb 20
67.7 LD
1.8 km
2000 PN9
Mar 10
45.5 LD
2.6 km
2002 DB4
Apr 15
62.5 LD
2.2 km
2008 UC202
Apr 27
8.9 LD
10 m
2009 UK20
May 2
8.6 LD
23 m
2008 FU6
May 5
75.5 LD
1.2 km
2003 YT1
May 5
65.3 LD
2.5 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 web 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 Dynamics Observatory
  Researchers call it a "Hubble for the sun." SDO is the most advanced solar observatory ever.
  3D views of the sun from NASA's Solar and Terrestrial Relations Observatory
Solar and Heliospheric Observatory
  Realtime and archival images of the Sun from SOHO.
Daily Sunspot Summaries
  from the NOAA Space Environment Center
  the underlying science of space weather
Science Central
  more links...
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