Owing to the fact that it is far easier for a chunk of Mars to travel to Earth than the other way around, it is likely that certain elements necessary to catalyze the formation of biological molecules (like RNA and DNA) came from our neighboring Red Planet. The vehicle for this interplanetary catalytic “seeding” was most likely a Martian meteor.
That’s according to a team of biochemists led by Steven Benner of The Westheimer Institute for Science and Technology in Florida.
Somewhere around 3.5 half billion years ago, the first biomolecules and then single-celled lifeforms emerged on our watery planet. There was “organic soup” aplenty…but one problem: just adding an energetic spark to this soup of molecules merely turns it into a tarry, sticky slime; supra-molecular forms like enzymes and RNA do not spontaneously self-organize in this mixture. No, what is needed is some type of substance — key metallic elements are ideal — that can serve as the catalysts, to get the whole thing rolling. As it turns out, there is a key element — one crucial for biomolecular formation here on Earth — that was lacking from the primordial Earth-scape but was plentiful on Mars.
In a report presented today at the annual Goldschmidt geochemistry conference in Florence, Italy, a team of geochemists (Benner et al) presented compelling evidence that an oxidized form of the metallic element Molybdenum was most likely this crucial, missing catalyst.
In a press statement, Benner elaborated:
“It’s only when molybdenum becomes highly oxidized 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 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.”
The geochemist team also stated that another metallic element, boron, could also serve this “jump-start” function here on Earth. However, water tends to impede the accumulation of boron (which is found here only in dry land masses) and there’s water aplenty here on Earth. But Mars – a dry planet — is ideal for boron accumulation.
According to Benner et al, all this water would make it extremely difficult for boron to aggregate in sufficient quantities to support the earliest stages of bio-evolution [note: land run-off of the element from flash-flooding river flows to the sea could have provided this resource].
A watery environment (whether a “warm little pond”, a clay-lined tidepool, deep under a glacier, or near a thermal vent on the sea floor) is believed to have been absolutely necessary to support the matrix of Life. As to the possible role for boron and its origin, Benner also stated:
“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,” he said
Further, Benner added, water is “corrosive to RNA”, the self-replicating supramolecule that many who theorize about the Origin of Life believe must have preceded the formation of DNA (a more complex molecule). This is known as the RNA World hypothesis (see: Author Comment, below).
See on planetsave.com