Don't worry—if we do find evidence of Martians, it will still be on Mars, we'll probably just have to dig a little deeper to find it. A new NASA study has concluded that if life ever thrived on the Red Planet, it probably did so underground, just below the planet's surface.
In other words, life may never have flourished on Mars, but could have done so inside it.
So what's got NASA playing with our prepositions? A fresh take on some old data. For years, European and NASA Mars orbiters have been snapping pictures like the ones up top to learn more about the Planet's geochemical makeup. Back in 2005, these photographs revealed the existence of clay minerals that suggested the planet once harbored a warm and wet environment. The only problem is, Mars' atmosphere as it exists today isn't thick enough to sustain such conditions, and there's no conclusive evidence to suggest it ever was.
At least, say NASA researchers, not on the planet's surface. For the last few years, planetary geologist Bethany Ehlmann and her team have been poring over images of Martian terrain in search of clues that could help explain the planet's mysterious past. One aspect of this search relies on the identification of various clay minerals (like the one discovered in 2005) that tell the researchers what sort of conditions (be they wet, hot, dry, or cold) they formed under.
The latest interpretation of this mineral-mapping data has led Ehlmann and her team to conclude that for the last several billion years, surface conditions on Mars have likely been too cold and too dry to support life; any signs of a watery past, conclude the researchers, were likely the result of brief, transitory periods when liquid water was stable at the planet's surface.
So does this mean we should abandon hope of findings Martian life? Of course not. If anything, NASA's latest findings can help us hone our search.
"If surface habitats were short-term, that doesn't mean we should be glum about prospects for life on Mars, but it says something about what type of environment we might want to look in," explains Ehlmann.