Theories about potential alien life crawling in Mars' red dust have been going viral even before there was an internet to go viral on, but (taken they exist) how are we going to find the Martians?
Though we’re more likely to find microbes rather than little green men, the search for anything remotely alive on Mars has come up as dry as the Red Planet itself, despite the galactic amounts of money spent by NASA and other space agencies to bombard it with rovers and lasers, send spacecraft flybys whizzing past, and orbit it with even more spacecraft that could provide some photographic evidence. Maybe Martian biosignatures aren’t what we Earthlings expect. Maybe they were obliterated by the harsh solar winds that stripped away its atmosphere. Maybe something is creeping around deep below the surface. Of course, there is always the possibility that maybe Mars is just barren.
It could be in the water (or lack thereof). While H2O has always been seen as that magical elixir of extraterrestrial life, its ability to make an entire planet flourish may or may not be valid outside Earth’s atmosphere. Geologist Jack Farmer of Arizona State University has another question.
"There are many indications of water on Mars in the past, perhaps reservoirs of water in the near subsurface as well," Farmer said. "But what is the quality of that water? Is it really salty—too salty for life?"
That would depend on the kind of life in question. If you’re talking about something as indestructible as a tardigrade, these “extremophiles” can plunge into a state of suspended animation for years when dehydrated. They only reanimate when conditions make it worthwhile. It could mean that potential life on Mars has just gone unconscious until survival on its hostile surface is possible again, but this is just one of many theories that could prove to be too far-out, even though we can now investigate with the technology of an entire chemistry lab shrunken down to fit on a computer chip. Not even that will unearth anything if we don’t know where to send it.
Theories of something existing deep beneath the Martian surface seem to make more sense. Anything from liquid water to fossils to living microorganisms could have survived without being radiation-bombed, but subterranean aliens could be dwelling extremely deep. This raises ethical concerns of planetary protection as well as the risk of thinking we discovered some sort of bizarre extraterrestrial life-form only to find that it was a bacterium from Earth that was a freeloader on the investigating spacecraft.
Scientists viewing the search for life from a different lens propose shifting the focus to seeking an actual habitat rather than just determining habitability. Just because a planet seems habitable by the standards of life as we know it on Earth does not mean anything actually thrives there. What some advise is setting up hi-res weather stations whose data may eventually indicate signs of where something might be lurking. The forecast would be far from stable. When you’re looking at a hypothetical habitat on a microbial level, the last thing you want to think of is a vast ecosystem. Variability on Mars means that any change in the weather could influence life to migrate. This would not result in a seismic shift, either, because the scale on which this would happen is so small it could literally fit in the palm of your hand.
“You are dealing on Mars with what I call extremophile extreme environments on steroids," observed the SETI Institute’s director of the Carl Sagan Center, Nathalie Cabrol, "and you don't look for microbial life with telescopes from Mars orbit."
Then there are those scientists who believe that we could actually be the biological relatives of these microbes whose existence has not yet been proven, making us long-lost Martians—but that’s a whole other theory.