You are viewing the page for Dec. 12, 2011
  Select another date:
<<back forward>>
SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
 
Solar wind
speed: 463.9 km/sec
density: 1.8 protons/cm3
explanation | more data
Updated: Today at 2347 UT
X-ray Solar Flares
6-hr max: B9
1859 UT Dec12
24-hr: C1
0838 UT Dec12
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 12 Dec 11
None of these sunspots poses a threat for strong solar flares. Solar activity remains low. Credit: SDO/HMI
Sunspot number: 103
What is the sunspot number?
Updated 11 Dec 2011

Spotless Days
Current Stretch: 0 days
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 11 Dec 2011


The Radio Sun
10.7 cm flux: 135 sfu
explanation | more data
Updated 11 Dec 2011

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/POES
Planetary K-index
Now: Kp= 1 quiet
24-hr max: Kp= 1
quiet
explanation | more data
Interplanetary Mag. Field
Btotal: 3.3 nT
Bz: 1.4 nT north
explanation | more data
Updated: Today at 2346 UT
Coronal Holes: 12 Dec 11
There are no large coronal holes on the Earthside of the sun. Credit: SDO/AIA.
SPACE WEATHER
NOAA Forecasts
Updated at: 2011 Dec 12 2200 UTC
FLARE
0-24 hr
24-48 hr
CLASS M
05 %
05 %
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: 2011 Dec 12 2200 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
05 %
05 %
MINOR
01 %
01 %
SEVERE
01 %
01 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
15 %
15 %
MINOR
10 %
10 %
SEVERE
05 %
05 %
 
Monday, Dec. 12, 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

SOLAR WIND: A minor solar wind stream is buffeting Earth's magnetic field. Arctic sky watchers should be alert for auroras. Aurora alerts: text, voice

SIGNIFICANT COMET PLUNGES TOWARD THE SUN: A comet nearly as wide as two football fields (200m) is plunging toward the sun where it will most likely be destroyed in a spectacular light show on Dec. 15/16. Although Comet Lovejoy (C/2011 W3) could become as bright as Jupiter or Venus when it "flames out," the glare of the sun will hide the event from human eyes. Solar observatories in space, however, will have a grand view. Yesterday the brightening comet entered the field of view of NASA's STEREO-B spacecraft:

"You can clearly see the comet heading diagonally through the images," says Karl Battams of the Naval Research Lab who prepared the animation. "During the 16-hour sequence, the comet brightens from magnitude +7.5 to +6, approximately."

It will soon grow much brighter. "This comet is a true sungrazer, and will skim approximately 140,000 km (1.2 solar radii) above the solar surface on Dec. 15/16," notes Battams. At such close range, solar heating will almost certainly destroy the icy interloper,creating a cloud of vapor and comet dust that will reflect lots of sunlight. The Solar and Heliospheric Observatory (SOHO) will have a particularly good view.

Discovered on Dec. 2nd by amateur astronomer Terry Lovejoy of Australia, the comet is an unusually large member of the Kreutz family. Kreutz sungrazers are fragments of a single giant comet (probably the Great Comet of 1106) that broke apart back in the 12th century. SOHO sees one plunging into the sun every few days, but most are small, no more than 10 meters wide. Comet Lovejoy is at least ten times larger than usual. Stay tuned for updates!

TOTAL LUNAR ECLIPSE: On Saturday, Dec. 10th, sky watchers across the Pacific witnessed a total eclipse of the Moon. During its hour-long transit through Earth's shadow, the Moon turned the color of the shadow itself--bright copper. The hue was meaningful to scientists who monitor lunar eclipses as part of their research on climate change. More on that below, but first regard this snapshot taken by James Barclay of Maidenwell, Queensland, Australia:

"The Moon looked like some alien planet hanging in a star-studded sky," says Barclay. "The excitement of those who witnessed this event will never be forgotten."

Dec. 10th Total Lunar Eclipse Gallery

Atmospheric scientist Richard Keen of the University of Colorado watched the event from Hawaii: "We had a fine warm morning for the eclipse here near Hale'iwa on Oahu'a North Shore. The eclipse was accompanied by the thunder of surf from the Banzai Pipeline, where later in the day surfers competed for the perfect ride," he says.

Keen wasn't just enjoying the view; he was also analyzing the event for scientific purposes. Lunar eclipses offer a unique way to assess the global dustiness of Earth's stratosphere. The scattering action of dust casts a red light into Earth's shadow. Lots of dust yields a deep red eclipse, while less dust produces a bright coppery hue.

The bright copper color of Saturday's eclipse suggests that the stratosphere is relatively clear. "My preliminary measurement of the brightness of the eclipse is magnitude -2.5 at mid-eclipse," says Keen. "It appears the clear stratospheric conditions of recent years is continuing."

This is important because the stratosphere affects climate; a clear stratosphere "lets the sunshine in" to warm the Earth below. At a 2008 SORCE conference Keen reported that "The lunar eclipse record indicates a clear stratosphere over the past decade, and that this has contributed about 0.2 degrees to recent warming."

The stratosphere has another effect on lunar eclipses. Note the soft blue colors in this picture from Shahrin Ahmad of Teluk Kemang, Malaysia:

This is the "turquoise fringe" often seen during total lunar eclipses. Keen explains: "Light passing through the upper stratosphere penetrates the ozone layer, which absorbs red light and actually makes the passing light ray bluer. This can be seen as a soft blue fringe around the red core of Earth's shadow."

More hints of turquoise may be found here, here and here.

  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 December 12, 2011 there were 1272 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Mag.
Size
2003 XV
Dec 7
1.1 LD
--
21 m
2003 WM7
Dec 9
47.6 LD
--
1.6 km
2000 YA
Dec 26
2.9 LD
--
80 m
2011 SL102
Dec 28
75.9 LD
--
1.0 km
2011 WS95
Dec 28
7.2 LD
--
49 m
1991 VK
Jan 25
25.3 LD
--
1.9 km
433 Eros
Jan 31
69.5 LD
--
8.5 km
2009 AV
Feb 16
44.9 LD
--
1.2 km
2000 ET70
Feb 19
17.7 LD
--
1.0 km
2011 CP4
Feb 23
9.1 LD
--
255 m
2008 EJ85
Mar 6
9.1 LD
--
44 m
1999 RD32
Mar 14
57.9 LD
--
2.3 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
Science Central
Trade Show Displays
   
  more links...
©2010 Spaceweather.com. All rights reserved. This site is penned daily by Dr. Tony Phillips.
©2013 Spaceweather.com. All rights reserved.