>If any fugitives from the spacecraft make their way to a survivable niche on Mars, we may never be able to tell whether biotic signatures later found the planet are traces of native life, or were left by escapees from our first Martian outhouse.
Even if life on Mars miraculously stumbled upon the same four (five) nucleobases, the same twenty (-two) amino acids, glucose, glycerol esters, and (deoxy)ribose, it would still seem pretty unlikely that it chooses the same three-base sequences corresponding to the same amino acids in RNA translation. But maybe we're still holding out hope for panspermia? And adaptable though our microbes are on megayear time-scales, we're also talking about the same cells that mostly can't survive intentional cultivation, as the author himself notes, so outcompeting the life native to Mars would be a real feat — merely surviving cold and dryness through dormancy is a well-known microbial swindle. I suppose it isn't impossible, but I have yet to hear a good argument that it's feasible.
But overall I agree, Mars has nothing. It's not even very big: the surface of Mars is roughly the size of the Pacific Ocean, well below doubling what we started with. Meanwhile, the asteroids are full of palladium.
Even if life on Mars miraculously stumbled upon the same four (five) nucleobases, the same twenty (-two) amino acids, glucose, glycerol esters, and (deoxy)ribose, it would still seem pretty unlikely that it chooses the same three-base sequences corresponding to the same amino acids in RNA translation. But maybe we're still holding out hope for panspermia? And adaptable though our microbes are on megayear time-scales, we're also talking about the same cells that mostly can't survive intentional cultivation, as the author himself notes, so outcompeting the life native to Mars would be a real feat — merely surviving cold and dryness through dormancy is a well-known microbial swindle. I suppose it isn't impossible, but I have yet to hear a good argument that it's feasible.
But overall I agree, Mars has nothing. It's not even very big: the surface of Mars is roughly the size of the Pacific Ocean, well below doubling what we started with. Meanwhile, the asteroids are full of palladium.