12-1-2012, 11:00 AM
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#353
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Join Date: Nov 2007
Location: I live in the last place where you Look.
Age: 31
Posts: 7,376
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Re: Terry's Astronomy Thread.
What's in the sky tonight?
December 1, 2012
-Since Jupiter just about at opposition, the asteroids Ceres and Vesta in Jupiter's vicinity are near opposition too. Vesta has brightened to magnitude 6.6, Ceres 7.2. Spot them here. They're near the horns of Taurus. This evening you'll have the darkest view of them shortly before moonrise. (The Moon rises around 7 p.m. depending on your location.)
Astro Picture of the Day:
December 1, 2012
Source:
Innermost planet Mercury would probably not be a good location for an interplanetary winter olympics. But new results based on data from the Mercury orbiting MESSENGER spacecraft indicate that it does have substantial water ice in permanently shadowed regions within craters near its north pole. The possibility of ice on Mercury has been entertained for years, inspired by the discovery of radar bright, hence highly reflective, regions near the north pole. Highlighted in yellow in this map based on projected MESSENGER images, radar bright regions are seen to correspond with floors and walls of north polar impact craters. Farther from the pole the regions are concentrated on the north facing crater walls. MESSENGER's neutron spectroscopy and thermal models for the craters indicate material in these regions has a hydrogen content consistent with nearly pure water ice and is trapped in an area with temperatures that remain below 100 kelvins (-280 deg.F, -173 deg.C). In circumstances similar to permanent shadows in craters of the Moon, debris from comet impacts is thought to be the source of ice on Mercury.
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