Astronomy

A small and very faint comet has surprised observers around the world by overnight becoming bright enough to see with the unaided eye.

Comet Holmes, which was discovered in November 1892 by Edwin Holmes, in London England, was no brighter than magnitude 17 in mid-October - that's about 25,000 times fainter than the faintest star that can normally be seen without any optical aid. In order to view an object this faint, one would need a moderately large telescope.

But the comet's brightness has suddenly rocketed all the way up to 3rd-magnitude, brightening nearly 400,000-times in less than 24-hours! On this astronomers scale, smaller numbers mean brighter objects. From urban locations, a 3rd-magnitude object might be hidden by light pollution, but under rural skies it would be clearly visible.

I reported previously about the Messier marathon, a race to find as many Messier objects in one night. The Messier Planner is a great tool one can use in order to prepare a marathon night. Or just use it as a handy planner for an sudden night of star watching.

DeepskyLive is a great java applet which behaves like an online star atlas, capable of showing stars up to magnitude 11.5 and deep-sky objects up to magnitude 16. You can easily locate different deepsky objects and print out detailled finder charts. Very handy if you don't have your own star atlas at hand.

In the latest version of Google Earth, an interactive sky map of the universe has been added. With Google Sky, people can explore millions of stars and galaxies; the data has been supplied by different organisations, among which the ESA.

While Opportunity is getting prepared to enter the Victoria crater, large dust storms are raging across the Martian dune planes. As dust collocation on the robots weakens their battery life, scientists anxiously await the end of the storms.

In the mean time, all we can do is have a look at PanCam, another amateur site which is doing great stuff with the photographic material being sent from Mars.

Here's an interesting link for comet chasers : Skyhound.com 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.

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.

AstroWhatsup.com 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.