Curiosity keeps finding evidence that Mars was once habitable

Layers of sedimentary rock in Gale Crater photographed by Curiosity, which serve as evidence of an ancient lakebed. (NASA/JPL-Caltech/MSSS)

In 2014, the Curiosity probe's big Mars discoveries kept coming. Most recently, in December, it discovered evidence of an ancient lakebed, as well as organic molecules and mysterious plumes of methane gas. Together, these findings and other data have many scientists convinced that Mars was once warmer and wetter than it is today — and perhaps even home to life.
In 2015, the rover will climb a giant mountain called Mount Sharp, sampling a succession of rock layers that will help us learn more about the planet's geologic and atmospheric history.