Given that the Ryugu sample was contaminated, how confident are we that these samples werent also contaminated?
https://phys.org/news/2024-11-ryugu-asteroid-sample-rapidly-...
https://phys.org/news/2024-11-ryugu-asteroid-sample-rapidly-...
> Key to the curation process was the use of so-called “witness plates”—flat plates made of aluminum and sapphire—that were exposed to all the same conditions as the sample from Bennu, creating a detailed record of potential contaminants.
> If a compound found in the Bennu sample wasn’t on the witness plate, scientists could confidently identify it as originating from Bennu. This is critical when dealing with organic compounds, where contamination can make it hard to distinguish what is truly extraterrestrial.
This is a very strong indication that the amino acids in the sample where made by an inorganic process.
That is, while life on Earth is left-handed, I don't know of any reason to assume that life elsewhere must be either left- or right-handed.
I don't actually believe in panspermia. I just think that it's important to not infer more than the evidence actually gives.
or the process is inorganic which we know couldn't favor left or righthandedness in the first place.
I would not be surprised if we find life in other planet/moon that use "only" [1] right handed amino acids. But it looks like it's easier to produce "only" one type of them: "only" left handed or "only" right handed.
To produce both in a 50%-50% ratio they would need to duplicate most of the enzymes, or have a specialized enzyme that transform one into the other. It's not impossible, but it seams to be wasteful.
Nobody is sure, but our current best guess is that life in other planets/moons will choose left or right instead of a 50%-50% mix.
[1] Life on Earth use a small amount of right handed amino acids, so I expect a "mirror" life to use a small amount of left handed amino acids.