Titan, the deep-frozen moon of Saturn, is emerging as the most likely place in the solar system for new life to evolve, according to scientists who have been studying its atmosphere and surface chemistry. They found that Titan's atmosphere is drenched in a wide range of complex organic molecules very similar to those that gave rise to life on Earth billions of years ago. Although it is far too cold for life at present, this is likely to change because stars such as the sun expand and grow far hotter as they reach old age. "About 4-5 billion years from now Earth will have been engulfed by the sun but the frozen outer planets are likely to be much warmer, including Titan,' said Professor Andrew Coates, of University College London's Mullard Space Science Laboratory. "The organic chemistry on its surface is already very similar to what we think existed on Earth before life developed. When it gets warmer, life will have a good chance to get going,' he said. The new insights into Titan, the largest of Saturn's 22 known satellites, stem from the torrents of data being sent back from the Saturn system by the Cassini probe, which arrived there in 2004 and is still in orbit. In 2005 it also released the Huygens probe which parachuted onto Titan's surface. The results have been undergoing detailed analysis ever since and make it ever clearer that the conditions on Titan have many similarities to those on the primordial Earth. In particular, they showed that the atmosphere, which had the appearance of a thick yellow smog, was made up of clouds of methane and nitrogen, while on the surface lay great lakes of hydrocarbons, rich in the kind of organic molecules needed to kick-start life. The conditions are unlike those on Mars, the next planet to Earth moving out in the solar system, which is now thought to be "too salty' to sustain life because of a high concentration of minerals in its water. Last week leading planetary scientists from Europe and America gathered at the European Space Agency's technical centre in Noordwijk, Holland, to draw up plans to send a new mission to the Saturn system around 2016. Athena Coustenis, a European planetary scientist who is pushing for a new mission to the Saturn system, will reveal details of the potential enterprise in Boston. SUNDAY TIMES, LONDON One of Saturn's rings