I’m curious about the hitchhikers that will make the trip to Mars with humans. Each human who goes on the trip is a complete ecosystem consisting of millions of species of single-cell and multi-cell organisms. The success of these hitchhikers, which colonize both the inside and outside of our bodies, just may become the real Mars story from a long term, evolutionary standpoint.
Hitchhikers have always played a role in human exploration and colonization. For example, diseases and parasites traveling in and on the bodies of Western colonists and explorers devastated native populations. This made it easier for Europeans to conquer the New World as an invasive species. In the best-case scenario, the Mars colonists will live long enough to have their population replenished from Earth, and a thriving colony will be established. The worst case is a Roanoke situation where everybody dies and no one knows how or why.
But will all life cease with the death of the humans colonists? What about all of those micro-hitchhikers? It’s highly unlikely that they would all die off just because their hosts do. Life has been discovered in all kinds of environments that were once thought to be barren. From smoldering pots on the bottom of the ocean to glaciers covering Antarctica, life tenaciously evolves in new ways and environments to reproduce itself.
Every bacteria and microorganism carries the genetic building blocks of all life on earth. In a decades-old experiment with simple E. coli bacteria at Michigan State University, twelve identical bacteria colonies have evolved into distinct new species with each finding new ways to extract nutrients from their environment. No matter how long the human colony on Mars lasts, the hitchhiking microbes could last longer. Yes, Martian conditions are harsh, maybe even harsh enough to have killed any life that may have existed there in the past. On the other hand, micro-biotic life may still exist on the Red Planet.
Bacteria are a hardy bunch. They can retreat into spores that have an indefinite shelf life. The spores may even be able to withstand the rigors of space without a spacecraft to protect them. There is some evidence that life might have hitched a ride to Earth on chunks of space rock, maybe even ones that were blasted off of Mars by a meteor impact. If so, life may be returning to the planet it came from. And if there are any original Martian life forms hiding as spoors, the presence of humans providing warmth and liquid water might be all that’s necessary to reawaken a slumbering Martian ecosystem.
Active or hibernating, those ancient bacteria will inevitably interact with our own personal ecosystems. Combining the genes of Martian bacteria with the genes of the hitchhikers from earth could create a whole new kind of space traveler. And even if there is no life on Mars to reanimate, at least one of our Earth life forms will find a way to adapt to the Martian environment. The longer humans stay on Mars, the more likely this event will occur.
We humans tend to be narcissistic. We see everything from a human viewpoint. A journey to Mars will be a great accomplishment for all of mankind. Like dogs carrying seeds caught in their fur from one place to another, we may be spreading life on a cosmic scale. However, unlike our animal brethren, we are capable of being conscious that we do so.
