Written by Derek Kessler on
Tuesday, 19 February 2008
As it would turn out, the location on our planet with the largest reserves of organic material are not the oil reserves under Saudia Arabia or the natural gas pockets in Russia - it's on the surface of Saturn's moon Titan. Observations from the orbiting probe Cassini have revealed that not only are there literal lakes of organic methane and ethane - the hydrocarbons actually rain from the clouds.
Because Titan is covered in a thick layer of clouds, Cassini has only been able to map about one fifth of the moon's surface, and only then with radar soundings. The probe has found dozens of large lakes over 10 meters deep (the deepest point that the bottom still returns a radar reading), all filled with methane and ethane. Earth's known natural gas reserves total about 130 billion tons. Astronomers estimate that the larger lakes each hold at least that level of energy potential, which is enough to provide the residential energy needs of the United States for three hundred years.
The massive dunes that the radar has also discovered are believed to be made up of tholins - pre-biotic organic chemical compounds (a term coined by Carl Sagan). A band of dark dunes around the equator are believed to contain several hundred times the organic material of Earth's coal reserves.
Despite the overabundance of organic material, the likelihood of any ilfe being discovered or ever forming on the moon is very low due to the frigid surface temperatures, which top out at 90 degrees Kelvin (-183 C). The cold temperatures keep some of the methane liquid, though the unstable compound readily evaporates and breaks down. Based on the observations, the amount of methane currently on Titan would dissapear completely in a few million years. Unlike Earth, which has several readily available sources of methane (like bovines), we have yet to discover any source for the methane on Titan. The leading theories postulate that there are so-called cryovolcanos on Titan's surface that vent gases from within the moon.
As it would turn out, the location on our planet with the largest reserves of organic material are not the oil reserves under Saudia Arabia or the natural gas pockets in Russia - it's on the surface of Saturn's moon Titan. Observations from the orbiting probe Cassini have revealed that not only are there literal lakes of organic methane and ethane - the hydrocarbons actually rain from the clouds.
