August 29, 2013
New Evidence Suggests Earthlings Started Life As Martians
Lawrence LeBlond for redOrbit.com - Your Universe Online
Scientists have long posited life on Earth may have started somewhere else in the universe, many pointing to the Red Planet. Now, new evidence is emerging that may hold some truth to that long-debated theory.Professor Steven Benner, from the Westheimer Institute for Science and Technology, gave a speech today at the Goldschmidt 2013 conference in Florence, Italy describing how life on Earth may have kickstarted on Mars.
Benner said an oxidized mineral form of the element molybdenum, which is thought to be a crucial building block for the origin of life, could only have been available on the surface of our Martian neighbor some 34 million miles away and not here on Earth. He also pointed out “recent studies show that these conditions, suitable for the origin of life, may still exist on Mars.”
Scientists have long wondered how atoms first joined to create the three crucial components of life: RNA, DNA and proteins. The molecules that combined to form genetic material are much more complex than the carbon-based chemicals believed to have existed on Earth some three billion years ago, when life first began to take shape. Most scientists assume RNA was the first of these molecules to appear.
However, the process is much more involved than just RNA appearing on Earth.
"It's only when molybdenum becomes highly oxidized that it is able to influence how early life formed," explained Prof 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."
The research presented by Prof Benner tackles two paradoxes that make it difficult for scientists to comprehend how life may have jump-started on Earth.
The first is dubbed the “tar paradox.” Prof Benner explained all living things are made of organic matter, but if you add energy such as heat or light to the mix and let them be, they do not create life, but rather something more similar to tar, oil or asphalt.
"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," said Professor Benner. "Analysis of a Martian meteorite recently showed that there was boron on Mars; we now believe that the oxidized form of molybdenum was there too."
The second paradox is that life struggled to take hold on Earth because it was totally covered by water, preventing sufficient concentrations of boron to form, which is typically found in very arid climates, such as Death Valley. But also, water is corrosive to RNA, which scientists believe was the first genetic molecule to appear on Earth.
"What’s quite clear is that boron, as an element, is quite scarce in Earth’s crust," Prof Benner told BBC News, “but Mars has been drier than Earth and more oxidizing, so if Earth is not suitable for the chemistry, Mars might be.
"The evidence seems to be building that we are actually all Martians; that life started on Mars and came to Earth on a rock," said Prof Benner. "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."