Permanent Human Settlement of the Earth, Space and Ocean Frontiers

Monday, March 05, 2007

Islands in the Methane Stream

It is one of the most incredible images yet seen in the solar system. From the largest "moon" - in the solar system - Titan - (actually a planet in its own right that just happens to be orbiting Saturn) – the Cassini spacecraft has sent back photos of an expansive lake of liquid methane and in its middle, a huge island the size of Hawaii’s big island, completely surrounded by the liquid hydrocarbon. The scene is far colder than any temperature the earth has ever experienced – hovering at or below -289 degrees Fahrenheit. (Compare that to the lowest temperature ever recorded on earth – Vostok Station in Antarctica logged -129 Degrees F. on July 21st, 1983.) Here is NASA’s press release:

“The island (shown) is about 90 kilometers (62 miles) by 150 kilometers (93 miles) across, about the size of Kodiak Island in Alaska or the Big Island of Hawaii. The island may actually be a peninsula connected by a bridge to a larger stretch of land. As you go farther down the image, several very small lakes begin to appear, which may be controlled by local topography.

"We've always believed Titan's methane had to be maintained by liquid lakes or extensive underground 'methanofers,' the methane equivalent of aquifers. We can't see methanofers but we can now say we've seen lakes," said Jonathan Lunine, Cassini interdisciplinary scientist at the University of Arizona, Tucson.

Since lakes come and go with the seasons, they wax and wane over time. Winds might alter the roughness of their surfaces. Repeat coverage of these areas is expected to provide more information on these lakes. By passing over a lake in a different direction, Cassini may see the effect of prevailing winds in the changing brightness of the lake surface. On later passes toward the end of its prime mission, Cassini might see changes in the shape or size of lakes as winter yields to spring in the northern hemisphere.