Scientists hope that a remote lake on a dormant¹ Chilean volcano can provide clues to what life may have been like in a far more distant place -- the planet Mars.

A 10-member team placed special plates in the lake on Licancabur volcano, at an altitude of 20,000 feet，on Sunday to measure the effects of ultraviolet light on organisms living there.

The scientists, mostly from the United States, think learning how Licancabur organisms protect themselves may help researchers understand how life survived on early Earth and perhaps on early Mars as well.

The damaging effects of UV radiation intensify² at altitude and the air is very thin. And the lake is covered with ice most of the year, as would have been bodies of water on Mars.

"If there was life on Mars 3.5 billion years ago, it could have used defense³ mechanisms⁴ similar to those used by the organisms at Licancabur volcano to survive," said team leader Nathalie Cabrol.

The group, which includes science researchers from NASA and the SETI Institute, planned to spend two days at the lake, but weather conditions forced them to give up some of their research, which included a planned dive into the frigid⁵ lake.

The mission also included geological experiments in the area around the volcano and testing a two-wheeled vehicle called "MARVIN," which may be used in future Mars missions.

One of the group members said the experiments, were "very promising⁶" but sediment⁷ and water samples would have to be analyzed⁸ in a laboratory before conclusions could be drawn⁹. Another expedition will recover the UV plates next year.