The combination of blues and reds at the onset of totality was simply beautiful," says Westlake. "I took the picture using a Nikon D700 digital camera with a 11-inch Celestron telescope."

The luminosity of the eclipse reveals much about the state of Earth's upper atmosphere. University of Colorado Prof. Richard Keen explains: "At the distance of the Moon, most of the light refracted into Earth's shadow passes through the stratosphere. When the stratosphere is clear (not 'dirtied' by volcanic aerosols) the shadow and therefore the eclipsed Moon is relatively bright."

Keen observed the eclipse on Dec. 21st and was able to draw some conclusions. "Using an 8x reversed monocular, I estimated the visual magnitude of the eclipsed moon at mid-totality as -1.9. This compares with a 'clear stratosphere' value of -2.1 to give a volcanic aerosol optical depth of 0.004--essentially zero. The stratosphere remains clear."

This is timely and important because the state of the stratosphere affects climate; a clear stratosphere "lets the sunshine in" to warm the Earth below. Yesterday's bright eclipse reinforces a conclusion Keen reported at the SORCE conference in 2008: "The lunar eclipse record indicates a clear stratosphere over the past decade, and that this has contributed about 0.2 degrees to recent warming."

TOTAL LUNAR ECLIPSE: Earlier today, for the first time in 372 years, a total lunar eclipse occurred on the date of the northern winter solstice. Observers in North America were favored with an overhead view as the full Moon slipped in and out of Earth's eerie red shadow. Jonathan Sabin sends this picture from Ellenton, Florida:

Photo details: 10" Meade LX200, Nikon D300, prime focus,ISO 1250, 2s exposure

RARE LUNAR ECLIPSE: The lunar eclipse of Dec. 21st falls on the same date as the northern winter solstice. Is this rare? It is indeed, according to Geoff Chester of the US Naval Observatory, who inspected a list of eclipses going back 2000 years. "Since Year 1, I can only find one previous instance of an eclipse matching the same calendar date as the solstice, and that is Dec. 21, 1638," says Chester. "Fortunately we won't have to wait 372 years for the next one...that will be on Dec. 21, 2094."

ALL-CLEAR IN THE STRATOSPHERE: Earth's stratosphere is as clear as it's been in more than 50 years. University of Colorado climate scientist Richard Keen knows this because he's been watching lunar eclipses. "Since 1996, lunar eclipses have been bright, which means the stratosphere is relatively clear of volcanic aerosols. This is the longest period with a clear stratosphere since before 1960." Consider the following comparison of a lunar eclipse observed in 1992 after the Philippine volcano Pinatubo spewed millions of tons of gas and ash into the atmosphere vs. an "all-clear" eclipse in 2003:

Keen explains why lunar eclipses can be used to probe the stratosphere: "At the distance of the Moon, most of the light refracted into the umbra (Earth's shadow) passes through the stratosphere, which lies 10 to 30 miles above the ground. When the stratosphere is clear, the umbra (and therefore, the eclipsed Moon) is relatively bright. On the other hand, if the atmospheric lens that illuminates the Moon becomes dirty enough, light will be blocked and the eclipse will appear dark."

This is timely and important because the state of 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."

What will the eclipse 21st eclipse look like? "The stratosphere is still fairly clear, and the December 2010 eclipse should be normally bright," predicts Keen. "I welcome any and all reports on the brightness of future lunar eclipses for use in my volcano-climate studies. While actual brightness measurements (in magnitudes) made near mid-totality are most useful, I can also make use of Danjon-scale ratings of the ecl

GEO-QUIET: Although a solar wind stream is buffeting Earth's magnetic field, it's a gentle buffeting, and geomagnetic activity is low. Strong auroras are unlikely during the next 24 hours.

GREAT GEMINIDS: On Dec. 13th and 14th, Earth passed through a stream of debris sputtering from mystery-rock 3200 Phaethon. The result was the annual Geminid meteor shower. At maximum, international observers counted more than 100 meteors per hour. "Even clouds could not stop the Geminids from putting on a great display," says John Chumack of Dayton, Ohio. "Just watch this movie."

More Geminid highlights from around the world may be found in the gallery:

UPDATED: 2010 Geminid Meteor Photo Gallery
[NASA: "Geminids Defy Explanation"] [meteor alerts]

MAGNETIC ERUPTION : On Dec. 14th around 1530 UT, a filament of magnetism lifted up from the surface of the sun and--snap!--erupted. NASA's Solar Dynamics Observatory recorded the action:

The blast produced an hours-long C2-class solar flare and hurled a magnificent CME into space: SOHO movie. The expanding cloud is not heading directly toward Earth, but it might deliver a glancing blow to our planet's magnetic field two or three days hence. High latitude sky watchers should be alert for auroras.

GLOBAL ERUPTION ROCKS THE SUN: A global eruption on the sun has shattered old ideas about solar activity. Researchers presented their surprising findings at a press conference Monday at the American Geophysical Union meeting in San Francisco. Get the full story from Science@NASA.

Dec. 13, 2010:  On August 1, 2010, an entire hemisphere of the sun erupted. Filaments of magnetism snapped and exploded, shock waves raced across the stellar surface, billion-ton clouds of hot gas billowed into space. Astronomers knew they had witnessed something big.

It was so big, it may have shattered old ideas about solar activity.

"The August 1st event really opened our eyes," says Karel Schrijver of Lockheed Martin's Solar and Astrophysics Lab in Palo Alto, CA. "We see that solar storms can be global events, playing out on scales we scarcely imagined before."

For the past three months, Schrijver has been working with fellow Lockheed-Martin solar physicist Alan Title to understand what happened during the "Great Eruption." They had plenty of data: The event was recorded in unprecedented detail by NASA's Solar Dynamics Observatory and twin STEREO spacecraft. With several colleagues present to offer commentary, they outlined their findings at a press conference today at the American Geophysical Union meeting in San Francisco.

Explosions on the sun are not localized or isolated events, they announced. Instead, solar activity is interconnected by magnetism over breathtaking distances. Solar flares, tsunamis, coronal mass ejections--they can go off all at once, hundreds of thousands of miles apart, in a dizzyingly-complex concert of mayhem.

"To predict eruptions we can no longer focus on the magnetic fields of isolated active regions," says Title, "we have to know the surface magnetic field of practically the entire sun."

This revelation increases the work load for space weather forecasters, but it also increases the potential accuracy of their forecasts.

"The whole-sun approach could lead to breakthroughs in predicting solar activity," commented Rodney Viereck of NOAA's Space Weather Prediction Center in Boulder, CO. "This in turn would provide improved forecasts to our customers such as electric power grid operators and commercial airlines, who could take action to protect their systems and ensure the safety of passengers and crew."

In a paper they prepared for the Journal of Geophysical Research (JGR), Schrijver and Title broke down the Great Eruption into more than a dozen significant shock waves, flares, filament eruptions, and CMEs spanning 180 degrees of solar longitude and 28 hours of time. At first it seemed to be a cacophony of disorder until they plotted the events on a map of the sun's magnetic field.

Title describes the Eureka! moment: "We saw that all the events of substantial coronal activity were connected by a wide-ranging system of separatrices, separators, and quasi-separatrix layers." A "separatrix" is a magnetic fault zone where small changes in surrounding plasma currents can set off big electromagnetic storms.

Click to play a 3MB animation

The blast produced an hours-long C2-class solar flare and hurled a magnificent CME into space: SOHO movie. The expanding cloud is not heading directly toward Earth, but it might deliver a glancing blow to our planet's magnetic field two or three days hence. Stay tuned for a more refined analysis later today.

SPIRAL ASTEROID: On Dec. 12th, the International Astronomical Union issued a telegram (CBET nr.2583) announcing the discovery of a spiral structure around main belt asteroid (596) Scheila. Steve Larson of the Catalina Sky Survey (CSS) found the curious shape in images obtained Dec. 11th through the Catalina 0.68-m Schmidt telescope. Other observers have since confirmed the phenomenon. The following picture was taken on Dec. 12th by Italian astronomers Ernesto Guido and Giovanni Sostero using a remotely-controlled 0.25m telescope in New Mexico:

"This was the most spectacular sun halo I have seen in recent years from Stockholm," says photographer Peter Rosén. "It was visible for the whole (short) day." In addition to the sundogs, upper tangent arc, and 22° halo captured in the snapshot above, Rosén also witnessed "a 46° outer halo and a circumzenithal arc as ice crystals blew in gusts across the sun. What a show!"

Now is the time of year when low-hanging suns shine through high-floating ice to produce such vistas. People of the northern hemisphere should be alert for halos.

more images: from Jörgen Blom of Stockholm, Sweden; from Merelyn Davis of Burbank, CA; from Paul Ballard of Kungälv, Sweden; from Gary Brekke of Fargo, ND; from Shawn Johnston of Fargo, ND; from Joanna Fengler of Poznan, Poland

NEW SUNSPOT: A sunspot is emerging over the sun's northeastern limb, and it appears to be one of the largest of the new solar cycle. This composite image from NASA's Solar Dynamics Observatory shows the sunspot's dark core (inset) and plumes of plasma shooting up from the active region:

POSSIBLE EARTH-DIRECTED ERUPTION: A magnetic filament in the sun's northeastern quadrant erupted during the late hours of Nov. 30th. Click on the image to play a movie recorded by NASA's Solar Dynamics Observatory--and pay attention to the bright splash below the movie arrow:

The blast produced a B-class solar flare and hurled a bright coronal mass ejection (CME) into space. Preliminary coronagraph images from NASA's twin STEREO spacecraft suggest that the cloud might be heading toward Earth. Further analysis is required, however, to confirm that the CME is coming our way.