Life probable on any wet rocky planet

The emergence of life is probable on any wet, rocky planet, says Nick Lane, Ph.D., of University College in London. More specifically, a wet rocky planet with hydrothermal vents.

Black smoker

20 Apr 11 – Lane tells of Jacques Monod, who published Chance and Necessitysome 40 years ago. Monod maintained that “the origin of life was a freak accident, and that we are almost certainly alone in an empty universe.” Monod’s bleak assessment was opposed by Christian de Duve, who has argued that life is a “cosmic imperative”, and as such will arise throughout the universe.

Similar arguments still abound today. The late Steven Jay Gould held that if you could wind back the clock, life would evolve along radically different lines. Simon Conway Morris argued that you could wind back the clock, and humanity would enjoy a second coming.

Although Monod was one of the pioneers of molecular biology, notably the discovery of messenger RNA, he knew nothing about vents. “Black smokers were not discovered until 1977, seven years after his book, and one year after Monod died,” says Lane. “Black smokers are intensely hot.” They’re “a chimney pumping effluent straight out into the ocean.”

White non-smoker will not do

“White non-smoker will not do,” says Lane. “Alkaline hydrothermal vent” is rather less memorable than “black smoker,” Lane laments, so most articles about alkaline hydrothermal vents seem to be illustrated with pictures of black smokers.

“That will not do either,” Lane declares.

Sorry Dr. Lane, but I used the photo of a black smoker (above) because I couldn’t find one of a “white smoker.”

So what shall we call these vents? Lane doesn’t offer a replacement word. However, he does point out that alkaline hydrothermal vents are formed by the process of serpentinization, in which hot water reacts with ultramafic rocks from the Earth’s upper mantle, in particular olivine.

Since serpentinization is a global process, says Lane, it is “likely to occur on any wet rocky planet.”

Lane further opines that alkaline hydrothermal vents cannot be attributed to volcanism.

Maybe it’s a matter of semantics, but I wonder what else could heat ocean water by hundreds of degrees, other than some form of underwater volcanism? Would we say that the geysers at Yellowstone National Park – which are also considered hydrothermal vents – cannot be attributed to volcanism?

“Four billion years ago, such vents would have been the ideal hatcheries for life,” says Lane. “They provide essentially all the requirements needed for sustained abiotic chemistry and the beginnings of natural selection.”

The origin of life in alkaline hydrothermal vents

“Alkaline vents provide the thermodynamic driving force, abundant raw materials, sustained over scores of millennia, and the catalysts needed for each step in the same form as modern enzymes.”

Alkaline hydrothermal vent systems should be seen as the only model that explains the origin of life, says Lane. “It is hard to imagine life not emerging in such a system.”

See entire 18-page article:
Thanks to Jack for this link


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