Science & Technology

Why the 2018 Discoveries on Mars Give Us the Best Hope of Life Yet

Let's get something straight right away: there are no little green beings on Mars. Horror films about the Red Planet often show humans being eaten by something sinister and creature-like on Mars. Luckily, the reality is more subtle. Yes, we do have a hope of finding life on Mars — especially due to two new discoveries this year. But when we talk about life on Mars, we don't mean monsters. We mean microbes.

Related Video: This Is What Mars May Have Looked Like Billions of Years Ago

The Building Blocks of Life

This summer, NASA announced that the Curiosity rover — that awesome NASA workhorse that's been trolling the Martian surface for more than six years — stumbled upon a huge find. It found something called organic molecules. In this case, "organic" doesn't mean really expensive vegetables. It means that the molecules contain the building blocks of life.

Organic molecules contain the elements carbon and hydrogen, which are super-important to life on Earth. Our life is carbon-based, while water depends on hydrogen. Some organic molecules also include oxygen, nitrogen, or other elements. To be sure, finding organics is not a slam-dunk for life. But it sure gives us more hope. That's especially because these particular organic molecules are complex, not the simple kinds that Curiosity found in other years.

Curiosity is just the first stepping-stone to a set of more advanced NASA missions to search for direct signs of life in the near future. The European Space Agency's (ESA) ExoMars rover can directly analyze organics to find out how they're built, including if they favor a "left-hand" or "right-hand" configuration similar to how life appears on Earth. And NASA's Mars 2020 rover can not only look for signs of life but also cache the most promising rock samples on the surface for a future Red Planet delivery to Earth.

Liquid Gold, Martian Tea — Water, That Is!

Also this summer, scientists announced that the ESA Mars Express made an extraordinary find. Buried under the south pole appears to be a body of liquid water. We're not too sure how "liquid" this water is; early indications show us that it might be a slurry full of sand. (Some news reports called this underground water a "lake," but it's a little early to get that excited.)

What we need is more measurements and more ideas about what's lurking in this lake or soup or whatever. Mars Express discovered this through radar. In theory, NASA's Mars Reconnaissance Orbiter could also hunt down this liquid as it has radar that can see underneath the Martian surface, but in more than a decade of work on the Red Planet, it hasn't seen anything yet. We can assume scientists will redirect observations as soon as possible to confirm or deny the Mars Express find.

Assuming this find can be confirmed, what an awesome moment for the Mars environment! Liquid water is often associated with life. The surface of Mars is extremely dry, radiation-soaked, and wind-swept, but if microbes could bury underneath somehow, there's a chance that they could survive. Just maybe.

But hopes for life also rest on the activity of the Martian planet, since geology provides a source of energy for microbes. Luckily, NASA has a mission that will soon be on the case. The InSight lander safely touched down in late November and is deploying its instruments.

By early 2019, InSight will be searching for "marsquakes," volcanic activity, and other signs that Mars is indeed alive, at least geologically speaking. Biologically? The hunt is still on. But we've never been more excited to take part.

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Hear about the search for life from the experts in "Aliens: The World's Leading Scientists on the Search for Extraterrestrial Life," edited by Jim Al-Khalili. We handpick reading recommendations we think you may like. If you choose to make a purchase, Curiosity will get a share of the sale.

Written by Elizabeth Howell December 18, 2018

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