Cosmic Mysteries: Why the Search for Alien Life Matters

victor-lucas (63)in #science • 8 years ago

"Are we alone? Do we matter? What is the point of it all?" These questions have haunted humanity since its inception, an existential cry to the heavens that put us here seemingly at random. If we are alone, does that imply some kind of uniqueness? Something special about the human race? Or are we just some error, some accident, in the isotropic cosmic weave of time and space? But our existential outcry will mean something entirely different if it turns out that no, we are not alone.

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This series of posts on cosmic mysteries will discuss all the things out there that might be possible now and in the future, as well as the impact that those things might have on humanity. I have a deep and unwavering fascination with all things outside our realm of understanding as well as the possibilities of the future, stemming from my life-long passion for science-fiction and fantasy. With this series, I hope to spark the same passion in you!

I am not just referring to humanoid life forms with green skin, antennae, and big googly eyes. While it would be absolutely mind-blowing to discover such a being, these questions of "are we alone" will be just as affected if we discover microbes, or bacteria, or any other form of living organic matter on another planet. It would forever defeat assumptions and assertions of some sort of cosmic uniqueness and force the expansion of the human consciousness to embrace the ever-expanding universe. And the answers to these questions might well lay right next door, on that most famous and dreamed about planet: Mars.

Cover of Ray Bradbury's the Martian Chronicles" - Source

When the first Viking probes were landed on Mars in the 1970's many scientists despaired. The red planet was a desert wasteland, atmosphere destroyed by the solar wind, massive volcanoes erupting into the night, utterly inhuman. Our dreams of lifeforms on our closest neighbor died. But not for long. As the years passed, scientists (with the assistance of further satellites and probes) began to decode the greater complexities of the Martian landscape. Now, it has been proven conclusively that in the past, liquid water flowed on the surface of Mars and that it used to have a magnetic field, which together strongly suggest that in the past it was possible for life to exist on the surface of Mars.

While definitely exciting, recent scientific thought has turned away from the surface and started to think about penetrating to the interior. In the past decades, it has been discovered on Earth that small living organisms can survive in far harsher environments than previously expected. In what is known as the Earth's deep biosphere, organisms survive in conditions previously thought to be completely inhospitable to life. In fact, these lifeforms that were completely unknown at the time of the first Voyager probes are now thought to account for anywhere between 10% and 20% of all life on Earth. (Source) Some conditions in the deep biosphere of Mars are almost certainly similar to those found on earth. In fact, there have already been indicators that the sorts of organisms that live in Earths deep biosphere persist on Mars.

Microbial Life in the Earth's Deep Biosphere - (Source)

The ecosystem of the Earth's deep biosphere relies on methane as the main source of energy, and most organisms either consume or release it. On Mars, however, the existence of methane in the atmosphere is impossible, as sunlight and certain chemical reactions destroy methane. With no atmosphere to speak of, any methane found on Mars would have to have been released very recently. That was why it was so surprising when a dozen years ago, three separate teams of scientists (one using the European Space Agency's Mars Express orbiter, two observing from Earth) claimed to have found methane in the thin atmosphere of Mars. However, a short period later the methane readings vanished. Similarly, just a couple of years ago NASA's Curiosity rover driving across the Gale Crater reported methane releases on the surface. One theory is that there are methanogens and methanotrophs (microbes that produce and consume methane respectively) creating and destroying pockets of methane in the Martian soil.

Methanogens Under a Microscope - Source

All of these findings are based on the limited amount of observations we have been able to make based off of the rovers that have in the past and currently do explore the surface of Mars. The possibility of life currently existing on Mars is certainly still only within the realm of conjecture. However, we have never sent a rover that is able to drill into the core of the red planet, and we have certainly never sent any humans to the planet. It will perhaps require one of these two things to happen before we can know for certain whether or not organic life still exists on Mars.

Future Missions and Possibilities

ExoMars- The ExoMars missions are two European-led Mars probe missions currently being developed by the European Space Agency (ESA) in conjunction with the Roscosmos State Corporation, also known as the Russian Federal Space Agency. The first probe is set for launch later this year, and the second in 2018. The purpose of the missions will be to search for biosignatures in the soil of Mars, and as such their rover will have a 2-meter core drill for taking samples underneath areas where there used to be liquid water and where organisms might have survived cosmic radiation. While certainly not long enough to reach a region such as the deep biosphere on Earth, it is possible that 2 meters are deep enough for organic life to have survived.

The ExoMars Rover - (Source)

Mars 2020- the NASA is essentially the American equivalent of ExoMars, with NASA sending a rover with the express intention of assessing past habitability and the possibility of current life.
Terraforming Mars - This possibility is significantly more theoretical than the previous two missions (which are definitely happening), but terraforming is really seen as the ultimate goal. It has long been asserted by a number of prominent scientists and global figures that humanity's only hope for long-term survival is expansion into the stars (think Stephen Hawking, Carl Sagan, Robert Heinlein, Elon Musk etc.)The idea of terraforming Mars, meaning artificially manipulating the atmosphere of Mars through the introduction of foreign elements so that it would rapidly become habitable for humans, has long been the goal of space-oriented scientists. I'll write another post on how we might go about doing that soon!