It was my understanding that the risk to terrestrial life from alien life contamination was essentially zero because there’s no reason to think they would have evolved to be able to infect anything on earth.
Consider the possibility of simple polymerizing molecules that are not living, but are biologically very active (and harmful). Prions are not chemically very complicated but can be incredibly lethal.
As far as my understanding goes, prions require contact with either the same or extremely similar proteins to have any affect, so they would require even greater biological similarity. Are their prion-like agents that work differently than I suppose?
> prions require contact with either the same or extremely similar proteins to have any affect
There is no requirement for similarity or sameness. Even if there aren't any that I know of that violate this - it's not in the definition that prions require contact with either the same or extremely similar proteins to have any affect.
Contamination doesn't even have to be self-replicating to be a major concern. Many organometallic compounds are exceedingly lethal and accumulate in biotic life. If alien tissue uses any to a significant degree, it would have disastrous consequences.
Obviously, the dangers of runaway self-replication makes even the smallest samples of primitive life potentially more deadly. And, while primitive life is far more likely in the universe at large, it is astronomically unlikely to reach our solar system undirected.
But when talking of other solar system bodies, like Mars, isn't it the other way around? I.e. astronomically unlikely that contaminants haven't already found their way to earth, undirected, for billions of years now?
Non interactive new life can be devestating on its own. Self replicating and no way to break down many of the byproducts. Consider what plastics do to the ocean and imagine new life that's equally indigestible.
I'm curious to see what they ultimately mean by "biological contamination". The objectives are so overly broad that they might be twisted enough to cut off colonization efforts.
> Planetary protection against "backward contamination" ensures that the Earth's biosphere is not adversely affected by the return of potentially hazardous microbes.
Without even getting past the title, a national strategy can't solve an international problem. Anymore than Kentucky can't solve the problems of the United States, the United States cannot defend the planet from asteroids or aliens alone. It will take pooling the resources of everyone into a central authority with the ability to effect allocation of financial and human capital to the proper programs.
Sure, but at the same time if a "biological contamination" were to happen elsewhere on earth there's no way the US would be able to protect itself alone from also being exposed.
