Article Posted on : - Dec 22, 2009

Saturn's largest moon -- Titan. A file photo

WASHINGTON (BNS): Scientists at California Institute of Technology discovered fog at the south pole of Saturn's largest moon -- Titan.

Sporadic layers of fog were spotted on the Saturn's moon 'Titan' which is formed due to the presence of methane gas.

In our galaxy Titan is the only place were which have copious quantities of liquid (largely, liquid methane and ethane) sitting on its surface, lead author Mike Brown said.

"It seems that earth and Saturn's moon share yet another feature, which is inextricably linked with that surface liquid: common fog," he said.

According to a media report, speaking at the American Geophysical Union's 2009 Fall Meeting in San Francisco, Brown and his team said, "The presence of fog provides the first direct evidence for the exchange of material between the surface and the atmosphere, and thus of an active hydrological cycle, which previously had only been known to exist on earth".

A "hyperspectral" imaging is done by the VIMS instrument which shows the large swath of the visible and infrared spectrum.

A Cassini data was collected by the team on the moon’s south pole from October 2006 to March 2007 from different online sources. The data was later differentiated in categories to get the different depths in the atmosphere, ranging from 20 kilometers (12.4 miles) to .25 kilometers (820 feet) above the surface.

” Evaporating methane on Titan, means it must have rained, and rain means streams and pools and erosion and geology. The presence of fog on Titan proves, for the first time, that the moon has a currently active methane hydrological cycle," Brown said.

“The presence of fog also proves that the moon must be dotted with methane pools, that's because any ground-level air, after becoming 100 per cent humid and turning into fog, would instantly rise up into the atmosphere like a giant cumulus cloud,” he added.

"The only way to make the fog stick around on the ground is to both add humidity and cool the air just a little. The way to cool the air just a little is to have it in contact with something cold, like a pool of evaporating liquid methane, “he said.