Mars' mysterious streaks might be caused by water boiling beneath its surface

Scientists may finally have an explanation for how water creates those mysterious streaks marking Mars' surface. A new study published Monday in the journal Nature Geoscience suggests that it's not salty water flowing downhill that's creating the streaks on the Red Planet as scientists initially thought, but rather water that's boiling out of Mars' soil.

With the help of a special chamber that modeled the climate conditions of Mars on a hot summer day, researchers were able to take some of the guess work out of deducing how water in Martian atmospheric conditions might behave. Scientists had previously thought the streaks were evidence of liquid water on Mars, but found this theory hard to prove — especially because Mars' exceptionally thin atmosphere makes it nearly impossible for water to stay in its liquid state for long.

When scientists put ice in the chamber with the same low atmospheric conditions found on Mars, they found it melted, as expected. But when the water started to boil, there was a surprise: When the boiling water emerged to the surface, it evaporated so quickly that it blasted dust and debris off the ground. The displaced dust exposed the darker ground underneath and created what appeared to be little ridges — not all that different from those streaking Mars' surface.

Watch the researchers' simulation of what's happening up on Mars, below.