Astrobiology researcher Dr Lynn J. Rothschild sampling microbial mats in a lake. These bacteria can survive conditions of high salinity, extreme temperatures and drought. Rothschild is studying such microbes to see if they could withstand the extreme conditions in space. This would support a revived version of the panspermia theory of the origin of life on Earth. This states that life may have spread through the solar system as microbes surviving on the rock debris of meteoric impacts. Rocks from impacts on Mars could have transmitted life to Earth, and also life from Earth to Mars. A good candidate for extraterrestrial microbes are halophilic (salt-loving) bacteria.