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Solar wind
speed: 346.1 km/sec
density: 3.8 protons/cm3
explanation | more data
Updated: Today at 2349 UT
X-ray Solar Flares
6-hr max: X2
0027 UT Dec20
24-hr: X2
0027 UT Dec 20
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 20 Dec 14
Sunspots AR2241 and AR2242 have delta-class magnetic fields that harbors energy for X-class solar flares. Credit: SDO/HMI
Sunspot number: 156
What is the sunspot number?
Updated 19 Dec 2014

Spotless Days
Current Stretch: 0 days
2014 total: 1 day (<1%)
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%)

Update 19 Dec

The Radio Sun
10.7 cm flux: 213 sfu
explanation | more data
Updated 19 Dec 2014

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/Ovation
Planetary K-index
Now: Kp= 1 quiet
24-hr max: Kp= 3
explanation | more data
Interplanetary Mag. Field
Btotal: 6.2 nT
Bz: 4.7 nT south
explanation | more data
Updated: Today at 2349 UT
Coronal Holes: 20 Dec 14
There are no large coronal holes on the Earthside of he sun. Credit: SDO/AIA.
Noctilucent Clouds As of Nov. 22, 2014, the season for southern hemisphere noctilucent clouds is underway. The south polar "daisy" pictured below is a composite of near-realtime images from NASA's AIM spacecraft.
Switch view: Ross Ice Shelf, Antarctic Penninsula, East Antarctica, Polar
Updated at: 12-19-2014 09:55:04
NOAA Forecasts
Updated at: 2014 Dec 20 2200 UTC
0-24 hr
24-48 hr
85 %
85 %
40 %
40 %
Geomagnetic Storms:
Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm
Updated at: 2014 Dec 20 2200 UTC
0-24 hr
24-48 hr
30 %
40 %
30 %
20 %
20 %
05 %
High latitudes
0-24 hr
24-48 hr
10 %
10 %
25 %
25 %
65 %
60 %
Saturday, Dec. 20, 2014
What's up in space

Learn to photograph Northern Lights like a pro. Sign up for Peter Rosen's Aurora Photo Courses in Abisko National Park.

Lapland tours

WEEKEND MAGNETIC STORMS? NOAA forecasters estimate a 60% to 65% chance of minor geomagnetic storms this weekend when a pair of CMEs is expected to sideswipe Earth's magnetic field. High-latitude sky watchers should be alert for auroras after nightfall. Aurora alerts: text, voice

X-FLARE (UPDATED): Big sunspot AR2242 erupted on Saturday, Dec. 20th @ 00:27 UT, producing an intense X1.8-class solar flare. NASA's Solar Dynamics Observatory captured the explosion's extreme ultraviolet flash:

A pulse of X-rays and UV radiation from the flare reached Earth minutes after the explosion. This "solar EMP" ionized our planet's upper atmosphere and blacked out HF radio communications over Australia and the South Pacific. Below 10 MHz, transmissions were strongly attenuated for more than two hours.

The explosion also hurled a CME into space. Click to view a movie of the cloud as recorded by the Solar and Heliospheric Observatory:

Although the instigating flare was Earth-directed, it appears that the CME is not. The bulk of the cloud will sail far south of he sun-Earth line, missing our planet. Solar flare alerts: text, voice

Realtime Space Weather Photo Gallery

RADS ON A PLANE, CONTINUED: Regular readers may remember last month's reports by Dr. Tony Phillips of radiation measurements inside commercial airplanes. During a cross-country trip between Reno NV and Washington DC, he absorbed a dose of ionizing radiation equal to about 3 dental x-rays.

However, not every trip is so "radioactive." On Dec. 17th, he flew from Reno to San Francisco--a short hop over the Sierras to attend the American Geophysical Union meeting--and the dose was much less. These curves show his measurements during the flight:

Compared to last month's travel, there was relatively little radiation on this flight. From take-off to landing, the total dose was only about 3% of a dental X-ray -- a hundred times less than before.

Why so little? For one thing, the flight was brief, less than an hour long. Moreover, it was low. The cruising altitude of the small commuter jet was only 26,000 feet compared to as much as 39,000 feet for last month's cross-country flights. When it comes to "rads on a plane," altitude matters. The source of the radiation is cosmic rays from space; the closer you are to space, the more radiation you are going to absorb. Short, low flights like the Reno to San Francisco hop are best for avoiding exposure.

The data come from a pair of radiation detectors routinely flown to the stratosphere onboard Earth to Sky Calculus Space Weather Buoys. The pager-sized devices are sensitive to ionizing radiation such as X-rays and gamma-rays in the energy range 10 keV to 20 MeV. Ideally, the two detectors should register the same dose rates throughout the flight. Slight differences between the two curves are an indication of the uncertainty in the measurements.

It is important to note that the sensors Phillips carried onboard the plane do not detect one of the most important forms of radiation: neutrons. Neutrons provide much of the biologically effective radiation dose at altitudes of interest to aviation and space tourism. To account for these uncharged particles, the doses discussed above should be doubled or tripled. To improve our estimates of the total dose rate, the students of Earth to Sky Calculus are evaluating neutron detectors for future balloon missions and plane flights.

Realtime Space Weather Photo Gallery

Realtime Aurora Photo Gallery

Realtime Meteor 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. 20, 2014, the network reported 20 fireballs.
(19 sporadics, 1 December Leonis Minorid)

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 20, 2014 there were potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Miss Distance
2007 EJ
Jan 12
68.9 LD
1.1 km
1991 VE
Jan 17
40.6 LD
1.0 km
2004 BL86
Jan 26
3.1 LD
650 m
2008 CQ
Jan 31
4.8 LD
36 m
2000 EE14
Feb 27
72.5 LD
1.6 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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