Something worth noting in a lot of these discussions about extraterrestrial organic chemistry is that, assuming that things like electron orbitals and atomic ch

Something worth noting in a lot of these discussions about extraterrestrial organic chemistry is that, assuming that things like electron orbitals and atomic charge work the same across the observable universe, we'd expect to see a lot of the same organic molecules form in similar ways. Life is carbon-based because carbon is the lightest atom that allows for long-chain molecules; oxygen is going to be widely present because its electronegativity allows for a range of interesting interactions; and broadly a number of things like amino acids should be expected to form in similar ways because of the atomic interactions that lead to them. I don't know if we've got a similar theory for why organic molecules on earth exhibit the same chirality except path dependence, but it's possible there's an atomic reason the L-type became dominant here, too. An awful lot of this stuff isn't "a roll of the dice", but an outcome of the physics of atomic and molecular interactions, and we'd expect to see similar elsewhere given the presence of both the atomic constituents and excess energy in the environment.