searching for the virus of life
Life, uh, finds a way. But how would it finds its way on Mars?
Since we knew that Mars was a sphere of rock, we assumed that it may be habitable which is a big part of the reason why we're investing billions of dollars into scanning the planet for even the tiniest hint of life. So far we know that Mars was once wet and recently, we've had a whiff of methane that may or many not be produced and replenished by Martian microorganisms.
The problem with making a definitive call is the fact that methane can be produced by bacteria and geological processes and until we uncover a sample of actual Martian microbes, all we have are educated guesses and possible scenarios. The rovers on the surface of Mars couldn't to go to the epicenter of the methane emissions and start looking for life.
They're just not designed to do that. An exhaustive search for microorganisms would be done a lot faster and much more efficiently by a human mission to the red planet.
Our search for life on Mars brings up an interesting question. Is life a rare thing which would only happen if and when all the ingredients are right for it, is it like a virus which tries to make a home out of anything even remotely capable of sustaining a living organism or is it something in between these two extremes?
Take early Earth. Around 3.5 billion years ago, when we finally see a fossil record of something which resembles living things, the conditions on our planet's surface were extreme to say the least. Hyperactive volcanoes, enormous lava flows, boiling hot temperatures, the beginnings of what would become oceans glowing green with iron and other metals, constant impact events and an atmosphere choked with toxic greenhouse gases. And yet, basic organisms clung to life in what we would describe as nothing less than hellish.
But they didn't grow or develop in complexity. They couldn't. More complex forms need more room, more resources and a more stable climate to survive. Environment dictates the direction and the pace of evolution and until approximately 600 million years ago, the harsh climate of a fiery and oxygen starved Earth put the breaks on the process. Only a few microscopic changes could occur.
As soon as the global climate stabilized and bacteria which fed on carbon dioxide and oxidized the iron in the early oceans, helping to raise the oxygen content in the air to some 20%, life started getting more complex and elaborate as more and more complex living things could survive and pass on their genes to the next generation. Life on our planet seems to act a lot like a virus, trying to expand into any available niche to reproduce itself.
So if we adapt the same view to Mars, we could use the detection of a methane cycle to say that there's no reason why there shouldn't be life on red planet. After all, it's not like there we don't know of any bacteria which don't need oxygen to fuel their metabolism and give off methane. We have colonies of these microbes right here on Earth.
And if life managed to survive on our toxic and dangerous environment billions of year ago, why not on Mars? Maybe life is like some sort of inevitable virus? All the ingredients for it are abundant in comets, asteroids and nebulae across the known universe. It's just a matter of time until it rains down on a young planet and starts bonding into organic molecules, right? Unfortunately, until we find a Martian microbe to study in a lab, we will never know for sure.
