Mars today is a cold, dry wasteland—but things were likely much different billions of years ago. Since we started launching robotic missions to Mars in the 1970s, scientists have collected evidence that points to a warmer, wetter past for the Red Planet, where the surface was teeming with lakes and oceans that could have been home to life of some kind. It’s part of the reason NASA built and launched a new rover that launched last week to look for signs of ancient aliens.
But there’s no complete consensus on what Mars really looked like in the past. “The argument over the climate of early Mars is an old one” going back 40 years, says Anna Grau Galofre of Arizona State University. She’s the lead author of a new study published in Nature Geoscience that upends those dreams of a watery Mars, presenting new findings that suggest the planet’s