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Solar wind
speed: 318.4 km/sec
density: 4.6 protons/cm3
explanation | more data
Updated: Today at 2346 UT
X-ray Solar Flares
6-hr max: C1
1701 UT Dec24
24-hr: C1
1552 UT Dec24
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 24 Dec 13
Sunspot AR1934 has a 'beta-gamma' magnetic field that harbors energy for M-class solar flares. Credit: SDO/HMI
Sunspot number: 108
What is the sunspot number?
Updated 24 Dec 2013

Spotless Days
Current Stretch: 0 days
2013 total: 0 days (0%)
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

24 Dec 2013

The Radio Sun
10.7 cm flux: 136 sfu
explanation | more data
Updated 24 Dec 2013

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Planetary K-index
Now: Kp= 1 quiet
24-hr max: Kp= 1
explanation | more data
Interplanetary Mag. Field
Btotal: 6.4 nT
Bz: 0.4 nT north
explanation | more data
Updated: Today at 2347 UT
Coronal Holes: 23 Dec 13
Solar wind flowing from the indicated coronal hole could reach Earth on Dec. 26-27th. Credit: SDO/AIA. posts daily satellite images of noctilucent clouds (NLCs), which hover over Earth's poles at the edge of space. The data come from NASA's AIM spacecraft. The north polar "daisy" pictured below is a composite of near-realtime images from AIM assembled by researchers at the University of Colorado's Laboratory for Atmospheric and Space Physics (LASP).
Noctilucent Clouds
Switch view: Europe, USA, Asia, Polar
Updated at: 12-24-2013 11:55:02
NOAA Forecasts
Updated at: 2013 Dec 24 2200 UTC
0-24 hr
24-48 hr
35 %
30 %
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: 2013 Dec 24 2200 UTC
0-24 hr
24-48 hr
25 %
20 %
10 %
05 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
15 %
15 %
25 %
25 %
35 %
25 %
Tuesday, Dec. 24, 2013
What's up in space

When is the best time to see auroras? Where is the best place to go? And how do you photograph them? These questions and more are answered in a new book, Northern Lights - a Guide, by Pal Brekke & Fredrik Broms.

Northern Lights - a Guide

LAST-MINUTE GIFT IDEA: Would you like to give someone a solar flare for Christmas? There's still time. Gift subscriptions to our Space Weather Alert Service are available now. Sign up for text or voice. Merry Christmas!

CHRISTMAS CONJUNCTION IN SPACE: According to some scholars, the Star of Bethlehem might have been a close encounter between Venus and Jupiter. The two brightest planets in the night sky, merged, would have made a spectacle of Biblical proportions. This Christmas, NASA's STEREO-B probe is observing a conjunction of three planets--Venus, Earth and Jupiter:

Unlike conjunctions of the distant past, this one includes our home planet. STEREO-B is located on the far side of the sun where it can look back and see Earth along with other worlds in the Solar System. Only NASA's twin STEREO probes, equipped with their high dynamic-range Heliospheric Imagers, can witness this kind of conjunction.

From STEREO-B's point of view, Earth and Jupiter are less than 0.4 degrees apart, while all three planets fit in a circle 2 degrees in diameter. This meeting is not nearly as tight as the putative Star of Bethlehem conjunction ~2000 years ago. At that time Venus and Jupiter could have been as little as 6 arcseconds (0.00166 degrees) apart. Nevertheless, the ongoing display is still special because it's the first "Christmas Star conjunction" from space. Happy Holidays from STEREO!

Realtime Space Weather Photo Gallery

CRESCENT VENUS: Wondering where to point that telescope you got for Christmas? Here's a target that will blow your holiday socks off: Venus. Like the Moon, Venus has phases, and at the moment it is a slender crescent. Maximilian Teodorescu sends this Christmas Eve photo from Targoviste, Romania:

"I enjoyed another superb sunset with Venus dominating the southwestern sky," says Teodorescu. "The bright planet was visible even through cirrus clouds. Despite poor seeing conditions, the view through my refracting telescope was superb both at 30x and at 200x."

Every night the crescent grows thinner as Venus moves toward inferior conjunction with the sun in early January. Tonight, only 10% of the planet's illuminated hemisphere is visible from Earth. Because Venus is so thin, refraction in our atmosphere can produce a rainbow effect as colorful as any Christmas ornament. It really is a magical sight. More information is available from Sky and Telescope.

Realtime Venus Photo Gallery

ANALEMMA 2013: If you took a picture of the sun at the same time each day, would it remain in the same position? The answer is no, and the figure-8 shape traced out by the sun over the course of a year is called an analemma.

Japanese photographer "Shiraishi" stitched together more than 50 pictures spanning 12 months to reveal the analemma of 2013 over the city of Kumagaya-shi in Saitama, Japan:

"My analemma project started on December solstice in 2012 and finished on December solstice in 2013," says Shiraishi. "This photo contains the sun images from Jan. 18 to Dec. 22, that is, all the sun images are only in 2013."

The upper and lower tips of the "8" represent the solstices--the longest and shortest days of the year. Now the Japanese sun is at the bottom. Winter has arrived!

Other planets have analemmas, too. Not all are figure-8s, however. The shape depends on the tilt of the planet's spin axis and the eccentricity of its orbit around the sun. Martian analemmas resemble a teardrop, while Jupiter's analemma looks like a jelly-bean:


Click here and scroll down to learn more about alien analemmas.

Realtime Space Weather Photo Gallery

Realtime Aurora Photo Gallery

Realtime Comet Photo Gallery

  All Sky Fireball Network

Every night, a network of NASA all-sky cameras scans the skies above the United States for meteoritic fireballs. Automated software maintained by NASA's Meteoroid Environment Office calculates their orbits, velocity, penetration depth in Earth's atmosphere and many other characteristics. Daily results are presented here on

On Dec. 24, 2013, the network reported 19 fireballs.
(14 sporadics, 4 December Leonis Minorids, 1 Geminid)

In this diagram of the inner solar system, all of the fireball orbits intersect at a single point--Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). [Larger image] [movies]

On Dec. 23, 2013, the network reported 4 fireballs.
(4 sporadics)

In this diagram of the inner solar system, all of the fireball orbits intersect at a single point--Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). [Larger image] [movies]

  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 24, 2013 there were 1447 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Miss Distance
2013 XH22
Dec 18
1.9 LD
27 m
2013 YB
Dec 23
0.07 LD
2 m
2011 YD29
Dec 28
6.1 LD
24 m
2007 SJ
Jan 21
18.9 LD
1.9 km
2012 BX34
Jan 28
9.6 LD
13 m
2006 DP14
Feb 10
6.2 LD
730 m
2000 EM26
Feb 18
8.8 LD
195 m
2000 EE14
Mar 6
64.6 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.
  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
Space Weather Alerts
  more links...
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