These pictures are almost too hot to touch. Metallic photos of the sun make great Christmas gifts.
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QUIET SOLSTICE: Today, Dec. 21, 2010, at 23:38 UT, the sun will shine straight down on the southern Tropic of Capricorn, marking the beginning of winter in the north and summer in the south. Astronomers call this event a "solstice." It's a quiet one; the Earth-facing side of the sun is blank (no sunspots) and solar activity is very low.
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
"It was an absolutely gorgeous night for an eclipse!" says Sabin.
Sabin's photo captured not only the red light at the core of Earth's shadow caused by sunlight filtering through the stratosphere, but also the "turquoise fringe" caused by our planet's ozone layer. Pictures like this are golden for researchers who look at the colors of eclipses to diagnose the state of Earth's atmosphere. See "All-Clear in the Stratosphere," below.
UPDATED: Lunar Eclipse Photo Gallery
[NASA: "Solstice Lunar Eclipse"] [astronomy alerts]
more images: from Rod Lindley of Dallas, TX; from Kevin R. Witman of Cochranville, Pennsylvania; from John W. O'Neal, II of Amherst, Ohio; from Evan Ludes of Omaha, Nebraska; from John Stetson of Southport, CT; from Mark A. Brown of Carlisle, Pennsylvania; from Giancarlo Ubaldo Nappi of Belo Horizonte MG, Brazil; from Phil Harrington of Long Island, NY; from Mike Mezeul II of Sachse, Texas
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."
Keen predicted the appearance of this morning's eclipse: "The stratosphere is still fairly clear, and the December 21, 2010, eclipse should be normally bright. 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 eclipse. Please be sure to note the time, method, and instruments used in your reports." Submit your observations here.
2010 Geminid Meteor Photo Gallery
[NASA: "Geminids Defy Explanation"] [meteor alerts]
November 2010 Aurora Gallery
[previous Novembers: 2009, 2008, 2007, 2006, 2004, 2003, 2002, 2001, 2000]
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 21, 2010 there were 1167 potentially hazardous asteroids. 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.
| ||The official U.S. government space weather bureau |
| ||The first place to look for information about sundogs, pillars, rainbows and related phenomena. |
| ||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 |
| ||Realtime and archival images of the Sun from SOHO. |
| ||from the NOAA Space Environment Center |
| ||the underlying science of space weather |