In an infinite universe containing infinite matter, everything that appears once can be expected to appear an infinite number of times.
Yep.
But we do not live in such a universe. There are various cosmological theories (e.g., eternal inflation) which propose a multiverse, which would be infinite;
Eh. Not quite?
In the basic eternal inflation scenario, there is one, continuous universe. There are no walls or discontinuities. It is one physical thing. Each observer in it has a perspective of an observable universe, but that's a matter of perspective, not a boundary within the reality.
To say this is a multiverse would be to say that North America is a "multicontinent" just because a guy in Los Angeles and a guy in New York don't have line of sight on each other. It is a sort of "weak-multiverse", where the limits are your perception - an
observable universe.
This is not my subject of expertise, so I will direct your to others.
Wired article
Biological amino acids could have celestial or terrestrial roots. An experiment simulated their formation in deep space—but the mystery isn’t solved yet.
www.wired.com
Here's a paper on the animo acids for terrestial life having potential extraterrestial origin from 2017.
Life on Earth began somewhere between 3.7 and 4.5 billion years ago, after meteorites splashed down and leached essential elements into warm little ponds, say scientists. Their calculations suggest that wet and dry cycles bonded basic molecular building blocks in the ponds' nutrient-rich broth...
www.sciencedaily.com
Wired and Science Daily are popular science publications. See how each of those titles are questions, rather than assertions? That's not something that should be done when reporting actual science results - these are
speculative articles, meant to titillate.
Another from this year.
Amino acid concentrations from 2 particles returned from different touchdown sites on the surface of Ryugu are reported. Differences in chemistry suggest different levels of aqueous alteration are recorded at the 2 sampled locations.
www.nature.com
Nature is a far better source. And, we can look at the abstract/introduction here for a clue:
"...While it may have been possible to generate amino acids on the early Earth, only extraterrestrial sources have been found to contain abiotically synthesised (sp)
amino acids with enantiomeric excesses of L-amino acids. As such, an extraterrestrial origin for at least some of the building blocks of life has been proposed."
In a big way, this is saying, "At the point the petri dish was found, it was covered in biological life, such that we cannot tell if a particular chemical on the dish came from a biological process, a local chemical process, or came from outside the dish. So, it has been suggested that it came from outside the dish."
The relevant scientific aphorism is, "lack of evidence is not evidence of lack." That you can't find abiological sources today does not mean those sources did not exist before biology.
Moreover, the Nature paper
doesn't actually take a position on the matter. They are speaking of the formation of amino acids on meteorites. That they could be relevant to the origin of life on the planet is presented as a reason why the research might be interesting, but not actually the point. And, specifically, Nature is talking about
abiological creation of amino acids on meteorites. There is
zero implication in the article that the origin is from prior life outside the solar system.
When Nature mentions it, they refer to another article, from the Proceedings of the National Academy of Science (PNAS). And that's also a good source. But that article is about a model, not about physical evidence one way or another.
That article notes that the majority of the impacts that would have delivered amino acids to Earth would have happened 4.1+ Gigayears ago. The planet only
formed 4.5 Gy ago. And at that point, you aren't really saying that the origin is "extraterrestrial" in the sense folks probably want it to mean. After all, in a very solid sense, the water on the planet is just as "extraterrestrial". Heck, the
ENTIRE PLANET is extraterrestrial! The thing accreted from a nebula of gas and dust around the Sun, remember.
The more appropriate, thought less clickbaity, way to put the whole thing is that the origins of life may be part and parcel with the complex chemical dynamics of solar nebulae and the accretion and formation of planets, rather than solely due to chemical dynamics on the planet after formation.
And if you want to put it that more appropriate, less implication-laden way, then I'd find nothing worth arguing about in it. The phrasing implying that origin of life here is due to
life elsewhere is the problem.
Oh, and that without Animo Acids we wouldn't have life as we know it, so it's a necessary building block. This is an article from John Hopkins university from this year. So it's not just about "amino-acid-based-life" as if that's something different than what exists on the Earth.
In early Earth simulation co-led by Hopkins researchers, scientists gain insights into how amino acids shaped the genetic code of ancient microorganisms
hub.jhu.edu
The point was that
abiologic origin of amino acids seems like it could be common anywhere there are planets, and that life based on it could thus also be common - so if we find life elsewhere, our chemical underpinnings might be similar on that level, at least.