Mars may have had better chemistry than early Earth for life to start

Life may have started on Mars before arriving on Earth, a U.S. researcher has told a major scientific conference in Florence, Italy. Steven Benner from the Westheimer Institute for Science and Technology in Florida told attendees at the conference held by the European Association of Geochemistry his research on how the first molecules necessary for life were assembled supports an idea the Red Planet was a better place to kick-start early life billions of years ago than the early Earth was. Therefore, he said, life could have started on Mars before being transported to Earth on meteorites. RNA, one of the building blocks of life, needs to be coaxed into shape by "templating" atoms at the crystalline surfaces of minerals, he explained, but while minerals most effective at templating RNA would have dissolved in the oceans of the early Earth, they would have been more abundant on Mars. Minerals containing the elements boron and molybdenum are key in assembling atoms into life-forming molecules, he said, but the environment of the early Earth is considered to have been unsuitable for the formation of those minerals. "It's only when molybdenum becomes highly oxidized that it is able to influence how early life formed," Benner told the BBC. "This form of molybdenum couldn't have been available on Earth at the time life first began, because 3 billion years ago, the surface of the Earth had very little oxygen, but Mars did. "It's yet another piece of evidence which makes it more likely life came to Earth on a Martian meteorite, rather than starting on this planet," he said. "The evidence seems to be building that we are actually all Martians; that life started on Mars and came to Earth on a rock."