Life on Mars: Your Questions Answered

Does life exist on Mars now?

There is a slim chance that microbial life exists on Mars today, perhaps under the planet’s ice caps or in subsurface lakes detected by spacecraft like the European Space Agency’s Mars Express. Locations like these could protect life from the harsh conditions on the planet's surface. 

Because the kind of life that we think could exist on Mars today is microbial, it wouldn’t be spotted by the cameras of an orbiting spacecraft. Instead, there are ways we could detect it indirectly through chemical signatures linked to life called biosignatures. 

One such biosignature is methane, which can be created by both biological and geological processes. Curiosity has detected methane near its landing site in Gale Crater, but this isn't conclusive; the European Space Agency’s Trace Gas Express Orbiter has not found signs of the chemical in Mars’ atmosphere.

Could humans bring life to Mars?

When sending spacecraft to Mars to look for signs of life, it’s extremely important to make sure we don’t bring microbes along with us. Even though it takes months for a spacecraft to travel to Mars, hardy microorganisms could potentially survive the journey.

Every mission that lands on Mars must be thoroughly sterilized before it leaves Earth. Otherwise, instruments looking for signs of life might be fooled by life that came along with the spacecraft. Even worse, there is a slim but real possibility that Earthling microbes could survive and thrive on Mars, potentially interfering with any lifeforms that might already exist there.

The risk of contaminating Mars with Earthling microbes becomes even greater when considering future human missions to Mars. Human bodies are teeming with microbes, and it would be nearly impossible to contain them within a crewed Martian outpost. NASA, international space agencies, and private companies must work together to create planetary protection guidelines that balance the benefits of human exploration with the risk of contamination.

from The Planetary Society Articles https://ift.tt/3jSWQwK
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