“The evidence seems to be building that we are actually all Martians; that life started on Mars and came to Earth on a rock,” says Steven Benner of the Westheimer Institute for Science and Technology. “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. In addition, recent studies show that these conditions, suitable for the origin of life, may still exist on Mars."
“It’s only when molybdenum becomes highly oxidized that it is able to influence how early life formed,” said Benner. “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.”
Benner tackled two of the four paradoxes that make it difficult for scientists to understand how life could have started on Earth.
The Tar Paradox: organic molecules, given energy and left to themselves, devolve into complex mixtures, “asphalts,” better suited for paving roads than supporting Dwarwinian evolution. Any scenario for origins requires a way to allow organic material to escape this devolution into a Darwinian existence, where replication with imperfections, where the imperfections are themselves heritable, allows natural selection to avoid a tarry fate.
The Water Paradox: water is commonly believed to be essential for life. So are biopolymers, like RNA, DNA, and proteins. However, the biopolymers that we know find water corrosive. Any scenario for origins must manage the apparent need of life for a substance (water) this is inherently toxic to life.
Steven A. Benner, Planets, Minerals and Life’s Origin, presented at the 23rd Goldschmidt conference, 2013
Image at the top of the page shows Mars volcanoes Ceraunius Tholus and Uranius Tholus photographed by Mars Express. Although not active now, they were in the distant past. Click for a large, 3-D version.
Image credit: ESA/DLR/FU Berlin (G. Neukum)
The Daily Galaxy via Westheimer Institute for Science and Technology