NASA is reprising an old quest: a search for life on Mars.
The hunt for Red Planet residents began four decades ago, when the agency sent two spacecraft, the Viking landers, to Mars. Their task was to prove that this world, while red, is not dead.
The landers initially sent back data that seemed consistent with bacteria-like organisms in the soil. But further analysis caused this early optimism to sour. Was there life on Mars? NASA’s conclusion was: “Probably not.”
This wishy-washy answer was frustratingly ambiguous, especially for an experiment that cost $1 billion. So, NASA is now taking a different approach in its hunt for microbes on there. Unlike the Viking landers, Perseverance won’t look for chemical signs of metabolism. Instead, it will trundle around Mars’ gaunt landscapes in a searching for sediments. These could contain clues to organisms that pitched and swirled in long-vanished seas.
The rationale is simple: if Mars ever had life, the dead will surely outnumber the living, and are therefore more likely to be found. The landing site for Perseverance, Jezero Crater, looks like a former lake basin fed by a dried-out river, a happy hunting ground for a rover on the prowl for the desiccated remains of early inhabitants.
The samples cached by Perseverance will be collected and returned to Earth by a future mission, to be analyzed in terrestrial laboratories. There will be no “Eureka” moment for Perseverance; if Martians are found, they will be found on Earth.
But if it that happens, it will be more than an interesting science story. The parade of history will be split. Just as the past is now divided into “before” and “after” the Copernican revolution, so too will discovering long-expired Martian bacteria permanently change our self-regard.
There is, however, a caveat; something that could lessen the importance of finding (dead) life on Mars. If it turns out that such organisms were related to Earthly life – if both were built on DNA scaffolding – then we will have a demonstration that life can accidentally spread between worlds, hitchhiking on dirt clods kicked into space by meteor impacts. That would be interesting, yes. But far more portentous would be to discover that our solar system has had a “second genesis;” that life on Earth and Mars were fundamentally different. If life arose independently on these two planets, then we’d have strong evidence that life is not miraculous, but mundane: a cosmic commonplace.
It would then be a near-certainty that in other places among the trillion planets of the Milky Way life has evolved to a state of self-aware intelligence. Simply getting life started doesn’t guarantee this; there would surely be manifold worlds where life stalls out as pond scum. But that cannot be the case for every planet or moon that spawns biology. Intelligence has survival value. Smarts will out.
So, finding Martian life would compel us to abandon the notion that we are privileged, that humans are the sole sentient inhabitants of the universe. Indeed, we would not only have a strong indicator of cosmic company but could infer that it is widespread. In that panoply of life, there will surely exist beings that are far beyond our technical level. This is guaranteed by the fact that the Sun and its planets are relative newcomers to the universe, billions of years younger than the average solar system.
Such a realization would be as consequential to our self-image as when we learned that we are not separate from the fauna of our world, but simply a part of it.
Suddenly, we would confront the likelihood that everything we accomplish has parallels in the actions of unseen others, and that what we find beautiful and worthwhile must have a billion other definitions elsewhere. Scientists, who find joy in being the first to know something, would realize that countless other beings have learned it too. We could be certain that there are vast libraries of knowledge that we cannot enter.
And what of religion? Theology has famously railed against earlier discoveries that diminished our central position in the cosmos, from Galileo to Darwin. How would it react to learning that not only is our planet unremarkable, but so are its most celebrated inhabitants?
The response is likely to be a calm one. Religious objections to the idea of other beings on other worlds have largely evaporated. A Survata poll from 2013 showed that about one-third of the followers of major western religions are believers in extraterrestrial life. Even members of the Ca tholic Church, notorious for censuring Galileo, now say they cannot categorically claim that the powers of “self-awareness, rationality and free will” are unique to humans.
Perseverance could put us back on a road long traveled. In the 18th century, telescopes became powerful enough to discern the polar ice caps and surface markings on Mars. The Red Planet was the only world we knew where conditions might be similar to those on Earth. This likeness launched a durable belief in Martian life, and the Perseverance rover is the latest gambit by science to hunt it down, dead or alive.
But what may seem like a straightforward pursuit of a long-standing hypothesis would – if successful – have implications of great philosophical consequence. Protagoras wrote that man is the measure of all things. But thanks to some high-tech hardware lumbering across the dusty sands of a nearby world, that soon might cease to be true.
Originally published on NBC News.
