Extraordinary Things on Mars

Are we allowed to colonize Mars?

This article was inspired by some objections to Elon Musk’s plan to put 1 million people on Mars before the end of the century. It is not about the technical or financial objections but rather about the argument that we should not colonize Mars because it could potentially harm Martian life.

The idea of life on Mars has a relatively long history. Already in the 19th century people entertained the thought of contact with Martians. Around 1900, Percival Lowell became famous for speculating about a civilization on Mars after the astronomer Giovanni Schiaparelli had found canals there with his telescope. The sighted structures turned out to be an optical illusion but the idea of life on Mars never really died.

They couldn’t really have known back then, but Mars is arguably the most Earth-like place in the Solar System — even though it lacks things like an atmosphere or liquid water. Still, Mars is one of the most promising places to suspect life. This is one of the main reasons for why Mars is a preferred target for space missions. Since the end of the cold war in 1990, 7 space probes — some with landers — have been sent to Mars, which is only topped by 9 missions to the Moon (the other celestial bodies account together for 8 missions).

Obviously, the Mars landers don’t look for Little Green Men — it is incredibly unlikely that a species which evolved separately from us would look so similar to us. However, what the NASA scientists don’t rule out are some simpler life forms. Typically, they look for water and organic molecules that could be a clue for past or present Martian life.

But why care so much about the possibility of life on Mars? One reason is academic interest. Humans are generally curious and if we found life on Mars, it would help a lot in answering the question of how life originated on Earth. This is a valid reason and pretty uncontroversial.

However, since human colonization of Mars became a serious possibility, there has been another reason for why the existence of native Martian life is relevant: ethical concerns. The concern that we somehow harm Martian life. For example by introducing terrestrial bacteria which then reproduce until they have taken over and driven Martian life to extinction.

It seems to me that this is an unjustified concern; not because terrestrial life has the birthright to destroy everything that gets in its way. Rather my argument has to do with the general frequency at which life arises.