are we really all martians?

As the international race to explore Mars heats up, some writers are resurrecting an old hypothesis that life on Earth really started on the red planet.
mars al amal
Photo of Mars by the Al-Amal space orbiter

It feels odd to post a spoiler warning for a twenty year old movie, but etiquette demands that it’s done anyway. The movie in question is Mission to Mars and the grand revelation it offers is that humanity may have evolved on Earth but not on its own accord. Instead, we’re supposedly the result of ancient Martians who had to escape their dying planet seeding the nearest habitable world after leaving clues for their arguably intelligent descendants to follow them into an alien solar system. The movie is not what you’d call great. Pacing feels off and it seems to be on a quest to check off every lost-civilization-on-Mars trope from other equally forgotten sci-fi movies. But its premise is based on a real scientific hypothesis.

The idea is simple. We know that life can survive traveling across space and the fiery descent through the atmosphere. We also found Martian meteorites on Earth. And finally, we know that Mars may have been habitable during its first billion years or so. So, with all that in mind, some scientists asked if it’s possible that life on our world originated on Mars, made its way here, and took root, making us all Martians by proxy. It sounds pretty wild but entirely plausible given our current knowledge, and when science writers see that Mars is trending in searchers and need some clicks and eyeballs, they resurrect this hypothesis in the public eye. But if this idea is so plausible, why don’t we already teach it in science classes? 

Well, simply put, we don’t have enough evidence for it. If Mars was alive billions of years ago, the organisms in its briny oceans were likely quite simple due to a lack of time to evolve much complexity and harsh conditions. If we ever found fossils of these creatures on the red planet and compared them to the fossils of the earliest life we know of on Earth, we could move this hypothesis into the realm of theory should there be significant similarities. Of course, there are some things to keep in mind when we do that. With all the building blocks of life abundant in meteorites, asteroids, and comets, life far and wide could be related enough to provide false positives. In other words, there are far too many gaps and unknowns.

Hypotheses like this are a very simple case where educated speculation meets inflamed and ready imaginations. It’s hard to discard various iterations of the panspermia hypothesis, the idea that life on Earth came from space in some form and took root here, especially because it has a lot of good science behind it. But ultimately, evidence matters, and if we don’t have enough to safely and confidently rule in favor of a bleeding edge idea, we can’t do much with it but put it on a back burner until conclusive proof shows up, no matter how good the science and statistics behind the idea may be. That said, we should still bring them up once in a while just so we don’t forget that some amazing concepts are still out there waiting for someone to study them…

# space // astrobiology / mars / panspermia


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