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SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
 
Solar wind
speed: 494.8 km/sec
density: 0.6 protons/cm3
explanation | more data
Updated: Today at 2345 UT
X-ray Solar Flares
6-hr max: B4
2009 UT Feb19
24-hr: C1
0851 UT Feb19
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 19 Feb 12
A new sunspot is rapidly growing at the circled location. Credit: SDO/HMI
Sunspot number: 63
What is the sunspot number?
Updated 18 Feb 2012

Spotless Days
Current Stretch: 0 days
2012 total: 0 days (0%)
2011 total: 2 days (<1%)
2010 total: 51 days (14%)
2009 total: 260 days (71%)
Since 2004: 821 days
Typical Solar Min: 486 days

Updated 18 Feb 2012


The Radio Sun
10.7 cm flux: 104 sfu
explanation | more data
Updated 18 Feb 2012

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/POES
Planetary K-index
Now: Kp= 2 quiet
24-hr max: Kp= 5
storm
explanation | more data
Interplanetary Mag. Field
Btotal: 6.5 nT
Bz: 2.7 nT south
explanation | more data
Updated: Today at 2346 UT
Coronal Holes: 18 Feb 12
Earth is inside a solar wind stream flowing from the indicated coronal hole. Credit: SDO/AIA.
SPACE WEATHER
NOAA Forecasts
Updated at: 2012 Feb 19 2200 UTC
FLARE
0-24 hr
24-48 hr
CLASS M
10 %
10 %
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: 2012 Feb 19 2200 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
10 %
05 %
MINOR
01 %
01 %
SEVERE
01 %
01 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
15 %
10 %
MINOR
05 %
01 %
SEVERE
01 %
01 %
 
Sunday, Feb. 19, 2012
What's up in space
 

They came from outer space--and you can have one! Genuine meteorites are now on sale in the Space Weather Store.

 
Own your own meteorite

SUNSET PLANETS: The brightest planets in the night sky are aligning for a must-see show in late February and March 2012. You can start looking tonight. [video] [full story] [Images: #1, #2, #3]

AURORAS OVER THE USA: A solar wind stream hit Earth's magnetic field during the waning hours of Saturday, Feb. 18th. Although the stream was expected, the bright auroras it produced were not. Northern Lights spilled across the Canadian border into several US states including Wisconsin, Michigan, Nebraska, North Dakota, Iowa, and Minnesota:

Travis Novitsky took this picture from Grand Portage, MN. "My girlfriend and I were just settling in to watch a movie when the auroras made a surprise appearance," he says. "A quick look out the back door of my house revealed that, yes indeed, the lights were out! For the next hour and a half we were treated to a green glow peppered with dancing curtains of green, purple and red."

In Nebraska--yes, Nebraska--"I saw auroras on and off for approximately 2 hours from around 9pm to 11pm local time," reports Chris Allington of Crofton, NE. "There was a brief spell where color was visible to the eye with rays and bands." Allington stitched together a series of 20s exposures to create this movie.

At the height of the display, researchers at the Poker Flats Research Range outside of Fairbanks, Alaska, launched a suborbital rocket to investigate how auroras affect GPS systems. Several photographers in the area caught the rocket flying into the Northern Lights.

This episode might have been amplified by the action of a co-rotating interaction region or "CIR." CIRs are transition zones between fast and slow solar wind streams. Solar wind plasma piles up in these regions, producing density gradients and shock waves that do a good job of sparking auroras. Local solar wind data suggest that Earth moved through a CIR around 1500 UT on Feb. 18th. Aurora alerts: text, voice.

February 2012 Aurora Gallery
[previous Februaries: 2011, 2010, 2009, 2008, 2007, 2006, 2004, 2003, 2002]

more images: from Dirk S.Miller of Rice Lake, Wisconsin; from Shawn Malone of Marquette, Michigan; from Matthew Moses of Solway Township, MN; from Brian Larmay of Beecher, Wisconsin; from Shawn Johnston of Fargo, North Dakota; from Aaron Peterson of AuTrain, Michigan; from Bryan Hansel of Grand Marais, MN; from Randy Halverson of Madison, Wisconsin; from Rob Harrington of McBain, MI

SPY-SAT DISAPPEARING TRICK: US spy satellite Lacrosse 5 occasionally confounds observers by disapppearing: In a matter of seconds, it can fade more than three astronomical magnitudes. Is this a deliberate form of stealth? Most experts think not, but no one outside of classified circles knows for sure what is going on.

To investigate, French astrophotographer Thierry Legault used his satellite-tracking telescope to photograph Lacrosse 5 as it sailed 490 miles above Paris on Jan. 15, 2012, and he caught the spysat in the act of disappearing:

"During the passage, the brightness of the satellite decreased by 10 times in only 4 seconds (a loss of 2.5 magnitudes)," describes Legault. "After 33 seconds of [dark flight] it regained its original brightness. Lacrosse 5 often shows this very singular behaviour, which is called by other observers (especially Marco Langbroek) the 'disappearing trick.'"

Other Lacrosse satellites do not perform the same trick, at least not to this extent, suggesting that the design of Lacrosse 5 differs from its predecessors. The fade is likely caused by some sort of self-shadowing--e.g., maybe some part of the spacecraft such as its solar panels casts a shadow over the main body when the spysat changes attitude.

Even Legault's fine images do not reveal the answer. "The cause of the disappearing trick, as well as the precise shape of the satellite, remain unknown."

Readers, would you like to try catching the tricks of Lacrosse 5? Check SpaceWeather's Simple Satellite Tracker and Flybys App for local flyby times.


Comet Lovejoy Gallery
[previous comets: McNaught, Holmes, Lulin, Tuttle, Ikeya-Zhang]

  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 19, 2012 there were 1287 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Mag.
Size
2009 AV
Feb 16
44.9 LD
--
1.1 km
2000 ET70
Feb 19
17.7 LD
--
1.0 km
2011 CP4
Feb 23
9.1 LD
--
255 m
2012 CS46
Feb 25
2.7 LD
--
12 m
2008 EJ85
Mar 6
9.1 LD
--
44 m
1999 RD32
Mar 14
57.9 LD
--
2.4 km
2011 YU62
Mar 16
73.4 LD
--
1.3 km
1996 SK
Apr 18
67.2 LD
--
1.6 km
2007 HV4
Apr 19
4.8 LD
--
8 m
2011 WV134
Apr 28
38.6 LD
--
1.8 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.
STEREO
  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
Heliophysics
  the underlying science of space weather
Trade Show Displays
   
  more links...
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