What I Learned Today

I came across an article today describing the latest extraterrestrial ocean hypothesis — that one exists beneath the crust on Titan. That’s right, a subsurface ocean, in this case probably composed of water and ammonia. This is in contrast to the so-last-year news about methane lakes on Titan, which are widely accepted. Usually Enceladus or Europa get all of the press with regards to potential oceans, so this is pretty unexpected. From the article:

“Using data from the radar’s early observations, the scientists and radar engineers established the locations of 50 unique landmarks on Titan’s surface. They then searched for these same lakes, canyons and mountains in the reams of data returned by Cassini in its later flybys of Titan. They found prominent surface features had shifted from their expected positions by up to 19 miles. A systematic displacement of surface features would be difficult to explain unless the moon’s icy crust was decoupled from its core by an internal ocean, making it easier for the crust to move.”

I’m curious about these observations. I’m sure that the scientists involved have already applied an appropriately sized dose of skepticism to this subsurface ocean theory, but my gut reaction would be that an error in measurement is far more likely than a decoupled crust and core separated by a liquid ocean (where are you, Mr. Occam?). (In fact, if the displacements really are “systematic” then a measurement bias/error is an even more likely candidate explanation.) I’ll have to look for the upcoming article in Science!