Of all the planets scientists have studied over the years, Mars is the one that we know the most about. We’ve sent orbiters, probes, and rovers to the Red Planet, and we’ve gathered an incredible amount of data about the dusty world along the way. Unfortunately, the answer to one very important question still escapes us: Did Mars ever have life?
A new study published in Nature Communications doesn’t make a declaration one way or the other, but it does offer some very important supporting evidence for those who imagine Mars was once home to life.
The paper is based on readings taken within the Gale Crater, which is a large depression on the Martian surface created long ago by a massive impact. Today, it’s a dry and desolate place, but long ago it held water and was perhaps even home to a giant Martian lake.
The Curiosity rover, which has called the Gale Crater home since it arrived on the Red Planet several years ago, has revealed that the water within the crater was not only salty but had a relatively comfortable pH level. The combination of a rocky world, suitable temperatures, and mineral-rich water sounds mighty nice if you’re hunting for places that might have supported life, but proving life existed there is still going to take more work.
Evidence to suggest life existed on Mars is indeed mounting. Researchers know that water flowed on the surface and have even discovered organic molecules that could have been created by biological processes.
Going forward, missions like the Mars 2020 rover will give scientists a better idea of what the surface conditions of Mars may have been like many millions or billions of years ago. Eventually, a crewed mission to Mars could further this line of research, though it’s hard to know how long we’ll be waiting before scientists can say whether or not the Red Planet hosted life.