It might not just be men who are from Mars, claims a new study which suggests that all life on Earth actually began on the red planet. An element believed to be crucial to the origin of life would only have been available on the surface of Mars, it is claimed.
Geochemist Professor Steven Benner argues that the ‘seeds’ of life probably arrived on Earth in meteorites blasted off Mars by impacts or volcanic eruptions. As evidence he points to the oxidised mineral form of the element molybdenum, thought to be a catalyst that helped organic molecules develop into the first living structures. Professor Benner will present his findings to geochemists gathering today at the annual Goldschmidt conference.
‘In addition recent studies show that these conditions, suitable for the origin of life, may still exist on Mars,’ said Professor Benner, of the Westheimer Institute for Science and Technology in Gainesville, Florida. ‘It’s only when molybdenum becomes highly oxidised that it is able to influence how early life formed. ‘This form of molybdenum couldn’t have been available on Earth at the time life first began, because three 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.’ The research Professor Benner will present at the conference tackles two of the paradoxes which make it difficult for scientists to understand how life could have started on Earth. The first is dubbed by Professor Benner as the ‘tar paradox’. All living things are made of organic matter, but if you add energy such as heat or light to organic molecules and leave them to themselves, they don’t create life. Instead, they turn into something more like tar, oil or asphalt.
Prof Benner added: ‘Certain elements seem able to control the propensity of organic materials to turn into tar, particularly boron and molybdenum, so we believe that minerals containing both were fundamental to life first starting. ‘Analysis of a Martian meteorite recently showed that there was boron on Mars; we now believe that the oxidised form of molybdenum was there too.’ The second paradox is that life would have struggled to start on the early Earth because it was likely to have been totally covered by water.
Not only would this have prevented sufficient concentrations of boron forming – it’s currently only found in very dry places such as Death Valley – but water is corrosive to RNA, which scientists believe was the first genetic molecule to appear. Although there was water on Mars, it covered much smaller areas than on early Earth. Prof Benner 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. ‘It’s lucky that we ended up here nevertheless, as certainly Earth has been the better of the two planets for sustaining life. ‘If our hypothetical Martian ancestors had remained on Mars, there might not have been a story to tell.’
