A well written essay and compelling topic. However, I would question the premise of “interstellar biogenesis” at its foundation — regardless of how many amino acids have been found in asteroids (and assuming that these were not the result of contamination from Earth, similar to how DNA helicases from humans routinely contaminate biolabs where DNA amplification/hybridization is designed to occur). Specifically, and looking at the authors assertion that “the raw ingredients are found all throughout the Universe”…we find that this postulate is unproven (we have not explored “throughout the universe” yet, and may never). But, putting the claim’s foundation aside, and just looking at the reality of interstellar space (as we know it so far, which is quite limited)…we do not see all of Life’s ingredients (presuming that we have the right recipe) being present ALL AT ONCE IN THE SAME PLACE (and in the right proportions)…at least not yet. The author further claims that “pretty much every world that forms in the Universe today will have these primitive lifeforms being brought to it at the time the worlds themselves form.” This is a problematic statement: none of the ingredients listed by the author are “life forms” strictly speaking (even as some primitive enzymatic precursors might give birth to auto-catalytic forms). And, if we just look at the known geologic history of our planet (its roiling, unstable crust, wide-spread vulcanism, magmatic upheavals, tectonic shifts and subductions, etc.), it is hard to see how any of these precursor molecules would have survived during any violent proto-phase of planetary formation. It is more likely, in terms of probability and ‘life as we know it’, that these ingredients evolved after our planet formed, not prior to. Further, just looking at the worlds known to us right here in our solar system, we see that Life is quite rare and “sensitively dependent upon initial conditions”…We see that the world where Life thrives, Earth, is quite rare and special… principally because it is a “perfect” bio-reactor (however long it took to evolve to this state). Indeed, the formamide reaction (of water and hydrocyanic acid) is enough to generate all four nucleotide bases. In a laboratory, scientists bring together all that is needed to perform the reaction sought after. Interstellar space MIGHT do this, someday, in some remote corner of space…but, maybe it already has, through the formation of planets. While it may be fascinating to contemplate an interstellar origin to life (as with other panspermic theories), we should always remember that Earth is a life laboratory…however unintentionally it became so…all the ingredients for the ‘origins of (Earth) life recipe’ are found right here.
