* Astronomy

A team of astronomers has used infrared spectral images of Saturns moon, Titan, acquired with the Gemini North Frederick C. Gillett Telescope, to dispute an earlier claimed detection of widespread morning methane drizzle.
Titan, the second largest moon in the solar system, has long fascinated astronomers because it is the only moon in the solar system with a thick atmosphere. Adding to the fascination, its cold atmosphere (94 K or -180º C near the surface) has a number of interesting similarities to our Earths atmosphere. For example, its complex temperature profile (temperature vs. altitude) has the same overall structure as Earths and the atmospheric surface pressures are nearly the same. Also like the earths atmosphere, nitrogen is the dominant chemical species.
After nitrogen, methane is the most abundant chemical species in Titans atmosphere. It has sometimes been said that methane plays the same role in Titans atmosphere as water does in ours.

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This side-by-side view shows a newly discovered impact crater (left) compared with a previously discovered crater (right). The new crater was just discovered by the Cassini spacecraft's radar instrument during its most recent Titan flyby on May 12, 2008. This makes the fourth feature definitely identified as an impact crater so far on Titan -- fewer than 100 features are regarded as possible impacts.


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Credit: NASA/JPL

Both images are about 350 kilometres in width. The crater on the right was discovered by Cassini in 2005 and is shown here for comparison. It is 80 kilometres in diameter, with the radar illumination from above. Called Sinlap, this crater is estimated to be about 1,300 metres deep. The new feature pictured on the left, which has not been named yet, is bigger than the Sinlap crater with a diameter of about 112 kilometres.
The new crater is located at about 26 degrees north latitude, 200 degrees west longitude, in the bright region known as Dilmun, about 1,000 kilometres north of the Huygens landing site.

Cassini is on a course for a Titan flyby on May 12, at an altitude of 1,000 kilometres, for the first of two Titan northern hemisphere flybys that will wrap up the prime mission.
On this flyby, Cassini's radar will map the bright region of Xanadu, which was only partly imaged previously. This overlap in coverage may yield stereo views of the region. The radar team has targeted Hotei Arcus, as well as a possible cryovolcanic feature, Tortola Facula (informally known as the 'Snail'), which was visible in infrared images.

Source NASA

Titan and Earth have much in common, but not when it comes to sand.
On Earth, sand grains form by breaking things down, but on Titan, the opposite may be true - with much of the sand a product of building things up.
That's one theory Cassini scientists are considering after studying Titan's massive sand dunes with the visible and infrared mapping spectrometer on the Cassini Saturn orbiter. The new observations raise the possibility that much of the sand grows from hydrocarbon particulates fallen from the sky that, once on the ground, join together and become sand grain-size particles.

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