Scientists claim to have found strong evidence that suggests Saturn’s large moon Titan has a liquid water ocean beneath its crust, a finding they say has raised the prospect that the moon could host life.
Gravity maps pieced together from data gathered from Nasa’s Cassini spacecraft over five years revealed that Titan’s shape changes by about 10 meters due to Saturn’s gravitational tugs, a squishiness that is best explained by a liquid body of water relatively close to the surface.
Scientists don’t know whether the subterranean ocean is feeding lakes spotted on the moon’s surface. But, any ocean would most likely be made of water, which is heavier than the methane and ethane that dominate the pools of surface liquids.
The most likely explanation, said Luciano Iess, with Rome’s Sapienza University and colleagues, is that Titan has a liquid ocean between 50 and 100 kilometres under the surface.
“The evidence for an ocean on Titan is nearly as good as the evidence for an ocean on Europa,” planetary scientist Jonathan Lunine, with Cornell University, told Discovery News.
“That puts Titan in an elite class of objects that are uniquely qualified to possibly host life,” Lunine added. One of the biggest questions about Titan’s suitability for life is if the ocean touches rock, a source of minerals and a pathway for heat. Unlike Europa’s ocean, which sits on a rock floor, Titan’s water may be sandwiched between layers of ice, leaving it without access to minerals and temperature variations to spark life, the researchers said
For the study, published in journal Science, the team measured Titan’s gravity as Cassini flew by it six times between 2006 and 2011. The measurements were made by tracking minute changes in the pitch of radio signals travelling between the spacecraft and earth during the flybys.
They found that as Titan circles Saturn every 16 days, the moon gets squeezed. A similar phenomenon occurs on earth by the gravitational pull of the moon.
Saturn’s pull on Titan causes a 10-meter change. If the moon were solid it wouldn’t be as squishy.