Abiogenesis and exobiology

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Abiogenesis and exobiology

Postby davidm on November 28th, 2018, 7:17 pm 

Interesting interview today with the biologist P.Z. Myers at ExoLife. The topics were abiogenesis and exobiology.

It was a long interview, more than an hour I believe, and it got pretty in-depth.

There was nothing particularly new or earthshaking about, but it nicely summed up the latest thinking about earth life and exo-life.

For me, the most salient part was P.Z.’s discussion of necessity and chance in the arising of life. He starts out by arguing that life got started relatively early on earth after the earth cooled, suggesting it was not a chance event, but a necessary one, underpinned by basis chemistry — and biology, he says, is just chemistry. By “necessary” he does not mean logically necessary, but more or less physically entailed by how chemistry works. So the building blocks of proto-life are going to easily form and of course are even found in meteorites.

The chance part comes as things get more complex. Then there are more ways for things to go wrong just by chance alone — or go right by chance alone, in the movement from non-life to life. And he argues there is no firm demarcation between life and non-life — just a fuzzy continuum. Is a virus alive?

The current thinking, he says, is that life, or proto-life, arose in hydrothermal vents. The old ideas of a “primordial soup” and RNA world are given short shrift, though an RNA world, he says, may have come later. He identifies Europa as a good target to search for simple life, as it has a heat source and an underground ocean, which means hydrothermal vents.

From these ideas, he speculates that simple life may be relatively common in the universe, but complex life relatively rare. While simple life arose relatively early on earth, it took some three billion years for multicellular life to evolve. That’s a long time, and suggests such evolution may have been a very fortuitous event — the chance part of “chance and necessity.”

As to intelligent life similar to our own, we shouldn’t expect it, he says. He points out that the 3.8-billion-year experiment in life has produced exactly one species, us, able to build radio telescopes and space ships. And, as he notes, not only has our time on earth been incredibly minuscule compared to the age of the earth, but is not likely to last long. Our status as an intelligent species may also be questioned, of course — just look at who the U.S. “president” is.

He also speculates about life that is not as we know it, and is not dismissive of this idea. He points out that Miller-Urey did another experiment in which it was found that organic compounds also arose under very different (extremely cold) conditions than those in their original more well-known experiment. Myers speculates about silicon instead of carbon as a basis for life.

A very interesting discussion, highly recommended! :-)
Last edited by TheVat on November 29th, 2018, 10:38 am, edited 1 time in total.
Reason: Mod fixed Jovian moon
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Re: Abiogenesis and exobiology

Postby davidm on November 28th, 2018, 7:28 pm 

Er, somehow, for me, that link defaults to the end of the video, not the start. If it does so for you too, just click back to the beginning.
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Re: Abiogenesis and exobiology

Postby TheVat on November 28th, 2018, 7:45 pm 

The implications for the Drake equation are worth considering. And, for Trek nerds, the possibility of Horta. ("Dammit, Jim, I'm a doctor not a bricklayer!") Who were not on the tech path to radiotelescopes, as I recall. Will watch this week. I lean towards the rare intelligence conjecture (insert political joke here), that a sustained path towards complex multicellular life is difficult and clever-monkey civilization (i.e. high tech) rare.
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Re: Abiogenesis and exobiology

Postby edy420 on December 1st, 2018, 2:30 am 

As always, I'm skeptical.

Why take this theory, over the old primordial soup theory?

Why does it take billions of years. Could the same process not take 5 or 6 years given the the right conditions.
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