Saturn's moon Titan is covered by lakes of hydrocarbons (illustration). (c) Esa
Reading On Earth, oil, gas and maybe even coal could run out soon. But there is one place in the solar system where you can find almost unlimited amounts of these energy resources: the Saturn moon Titan. After the space probe Cassini has now scanned a fifth of the surface of the frosty moon with the radar, present researchers to Ralph Lorenz now a first inventory of titanium hydrocarbon deposits. The Cassini data shows several hundred lakes, especially near the North Pole. Several dozen of them alone contain more hydrocarbons than the entire oil and gas reserves of the earth, according to the model calculations of the researchers. Lorenz and colleagues are certain that the lakes are more than ten feet deep, as the radar waves would otherwise have penetrated to the ground. "Titan is just so covered with carbonaceous material, it's a huge factory for organic compounds, " says Lorenz.

The methane probably comes from inside the moon. In the atmosphere, the gas has a limited lifespan, as it is destroyed by ultraviolet solar radiation. In the gas shell of the orange moon, the carbonaceous fragments make larger organic molecules, the so-called tholines. They also rain again on the surface, especially near the equator, forming huge dune belts. In these dark hills hundreds of times more carbon is contained as in the entire coal reserves of the earth, write Lorenz and his colleagues.

However, considering the age of titanium, these are relatively small amounts. The amount of methane in the lakes is only enough for a few million years to maintain the concentration in the atmosphere. That means, write the researchers to Lorenz that the methane must be replenished by ice volcanism from the inside of the moon. It is therefore quite possible that the environmental conditions on the Saturn moon are subject to strong fluctuations. Methane is a strong greenhouse gas. If the material slowly disappears from the surface over the next few million years, then it could become much colder in the future than minus 179 degrees Celsius? the current temperature on titanium.

Ralph Lorenz (Johns Hopkins University, Baltimore) et al .: Geophysical Research Lettres, Vol. 35, p. L02206, doi: 10.1029 / 2007GL032118, 2008 Ute Kehse advertisement

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