According to a study, large craters on Saturn's largest moon, Titan, are the best places to look for the building blocks of life. Using images and data from the Cassini spacecraft and the Huygens probe, scientists led by Catherine Neish, of the University of Western Ontario, Canada, investigated the best places to search for biological molecules on the titanium surface.
The surface of Titan's abundant carbon-rich molecules (hydrocarbons), which have been shown to form amino acids, are the building blocks of proteins needed for life when exposed to liquid water in laboratory simulations. However, titanium is far too cold for liquid water on the surface. Cassini radar measurements, which orbited Saturn for 1
Cassini's radar revealed lakes, dunes, mountains, river valleys, and not many craters. This suggests that there are processes that re-emerge and fill or erode older craters. To find a world like the Earth nine times as far from the Sun was monumental, researchers said.
Although methane lakes may have been the obvious choice to look for signs of life, researchers have instead found craters and cryovolcanoes (regions where liquid water erupts under Titan's icy surface) among the most enticing places. Both properties promise to melt the icy crust of titanium into liquid water, a necessary step in the formation of complex biomolecules.
"When we mix Tholine (organic matter that comes from simple gas mixtures of cosmic rays) with liquid water, we make amino acids really fast," said Morgan Cable of NASA's Jet Propulsion Laboratory in the US. "Any place where liquid water is on or near the titanium surface could be the precursor to life – biomolecules – that are important to life as we know it, and that's really exciting," said Cable.