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Comet chasing


Here's an interesting link for comet chasers : presents a list of visible (by telescope, not necessarily with the naked eye) comets in the current month.



WikiSky is an interactive website like Google Maps, but then for the night sky. Where Google Maps has satellite images, Wikisky uses the Sloan Digital Sky Survey. Unluckily, not all areas are covered yet (try searching for the Orion nebula).



I recently joined a HP demo about integrity virtual machines, where I noticed that all demo machines had stellar names. One system being named Sulaphat, and being an astronomer myself, I wondered which star this would be. Apparently it's Gamma Lyrae, a blue giant star, which I found in The Electronic Sky, an astronomers wikipedia. Another place of interest is the Fixed Stars, where you can find more historical and astrological (ergo pseudo-scientific) information about several stars. Why do stars have such weird names ? Because the Arabs where the first to give them names.

Are you interested in learning the names of constellations and stars ? Head over to the Space Place, which offers you some printouts of sky views during several times of the year.

Methane lakes finally found on Titan


Titan has long intrigued space scientists, as it is the only moon in the Solar System to have a dense atmosphere -- and its atmosphere, like Earth's, mainly comprises nitrogen. Titan's atmosphere is also rich in methane, although the source for this vast store of hydrocarbons is unclear. Given that Titan is billions of years old, the question is how this atmospheric methane gets to be renewed. Without replenishment, it should have disappeared long ago. A popular hypothesis is that it comes from a vast ocean of hydrocarbons.

But when the US spacecraft Cassini sent down a European lander, Huygens, to Titan in 2005, the images sent back were of a rugged landscape veiled in an orange haze. There were indeed signs of methane flows and methane precipitation, but nothing at all that pointed to any sea of the stuff. But a flyby by Cassini on July 22 last year has revealed, thanks to a radar scan, 75 large, smooth, dark patches between three and 70 kilometers across that appear to be lakes of liquid methane.

They believe the lakes prove that Titan has a "methane cycle" -- a system that is like the water cycle on Earth, in which the liquid evaporates, cools and condenses and then falls as rain, replenishing the surface liquid.

What's up - 2007

Astronomy has another 2007 astro calender available for download (23 MB pdf). Very great overview of night objects for every skyhunter out there. The 2006 edition was a great success, the 2007 one looks as promising as the previous one.


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