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3.77-Billion-Year-Old Fossils Found, Could be Earliest Evidence of Life On Earth (theguardian.com)
An anonymous reader shares The Guadian report: Scientists say they have found the world's oldest fossils, thought to have formed between 3.77bn and 4.28bn years ago. Comprised of tiny tubes and filaments made of an iron oxide known as haematite, the microfossils are believed to be the remains of bacteria that once thrived underwater around hydrothermal vents, relying on chemical reactions involving iron for their energy. If correct, these fossils offer the oldest direct evidence for life on the planet. And that, the study's authors say, offers insights into the origins of life on Earth. "If these rocks do indeed turn out to be 4.28 [bn years old] then we are talking about the origins of life developing very soon after the oceans formed 4.4bn years ago," said Matthew Dodd, the first author of the research from University College, London. With iron-oxidising bacteria present even today, the findings, if correct, also highlight the success of such organisms. "They have been around for 3.8bn years at least," said the lead author Dominic Papineau, also from UCL.
I know it's a joke, but just for the sake of discussion I'd like to address it.
Finding out that life took 'only' 100 million years to appear after the formation of liquid oceans makes it a lot more likely that life (as we know it) is ubiquitous in favorable conditions. It means that if we are ever able to investigate the cosmos, we may find that most worlds that have liquid water have at least primitive life on them (rather than 'some' or 'occasional'). And there is always the possibility of life as we don't know it; life in gas giants, on neutron stars, in the gluon soup of the first moments of the cosmos (Stephen Baxter, but I can't remember which story), in the accretion disks of black holes, in the photosphere of stars.
There are so many ways that organization could form out of chaos, and that life would be invisible to us. If there was a form of life that lived in our sun's photosphere how would we tell it existed? We only recently learned that there are microbes in our upper atmosphere that is evolved to survive there permanently... and we flew through it for decades!
The more alien life is, the easier it is for us to overlook or not recognize the signs of its existence. Not only that, but the less likely we are to visit (or closely investigate) the environment it lives in because that environment is inhospitable to us.
So yeah... finding out that life evolved early on on Earth is fascinating, and it really lends weight to the possibility of life being all over the place... even where we have not tried to look.
"I will trust Google to 'do no evil' until the founders no longer run it." Hello Alphabet.
We know that simple organic compounds form spontaneously from anorganic matter. Amino acids like lysine or nucleic acids for instance appear, if you treat a mixture of water, carbondioxide and nitrogenium with lightning. So yes, organic compounds have been found in comets or meteorids, but that's because they are quite aboundant in space and form sponaneously given the right conditions.
Yes, some of those compounds on Earth might have arrived via a cosmic impact, but it seems they were just the literal drop in an ocean of organic compounds formed on Earth itself. And an asteroid impact sets free a large amount of energy, comparable to a nuclear detonation, which means that any more complex molecules have been destroyed by the impact.
And allthough organic matter forms spontaneously from anorganic matter, and organic matter can be transported via comets and other cosmic debris, if it arrives somewhere where life might form, there is a high probability that life has already formed there, when the organic matter arrives from space, and then it's just some additional nutrient for the local life forms, but it will not be the origin of a completely new life.