A moon of methane

The Cassini-Huygens mission – a joint venture between the European Space Agency; ASI, the Italian space agency and NASA – finished the Titan leg of its journey on Friday, January 14 with the historic descent onto the moon’s surface by the Huygens probe. (A total of 17 nations eventually contributed to building the spacecraft, with the Cassini orbiter built by NASA’s Jet Propulsion Laboratory, the Huygens probe by the European Space Agency and the Italian Space Agency providing Cassini’s communication antenna.) From now on, this extraordinarily interesting satellite, from a scientific point of view at least, will cease to be quite so mysterious. In the week that followed, scientists engaged in a feverish study of the data sent back to Earth with the help of the mother ship Cassini. Last Friday, January 21, the first findings from Titan were made public. Researchers stressed, however, that it will be many years before the data is fully processed. But so far, data has confirmed the resemblance of Saturn’s moon with Earth as it was 4 billion years ago, that is, a short while before organic compounds, through chemical reactions, gave birth to the first life forms. Titan is an astounding world with geophysical processes similar to Earth’s. Only the materials (largely methane) and the environmental conditions differ. The chemical processes are also different: Instead of liquid water, Titan has liquid methane; instead of silicate rocks as on Earth, Titan has water ice; hydrocarbon particles take the place of dust, and Titan’s volcanoes spew, not lava, but ice and ammonia. The photographs of the surface show an extensive network of drainage channels that run into methane lakes or seas. While the channels and lakes appeared to be dry, it had not been long since the last methane rainfall. Despite the existence of many factors (such as chemical compounds and volcanic activity) that give rise to life forms, the exceptionally hostile environment (-180 Celsius) has prevented their emergence.