A new study by a pair of U.S. geologists suggests Mars was once blitzed by a barrage of comets and asteroids “hundreds of kilometers in diameter.” But this cosmic event apparently made the Martian planet more habitable, not less. It could be a big reason why scientists are seeing signs of life seemingly everywhere they look.

The event would have occurred during the Late Heavy Bombardment about four billion years ago, heating Mars up to such an extent that life could have been supported. However, because of its size and distance from the Sun, scientists believe the small planet was unable to sustain its new-found atmosphere, eventually evolving into the barren landscape it is today.

Using a computer simulation, the geologists believe the Late Heavy Bombardment, which is estimated to have lasted around 100 million years, fractured the Red Planet’s crust and melting its subsurface ice. And, voila, you have an ocean. In the meantime, atmospheric temperatures may have increased, creating more habitable conditions for life.

However, Mars eventually reverted back to its cold and barren form after its atmosphere and oceans were stripped away. Although scientists believe there are signs of flowing water on Mars, it was more Earth-like than we initially thought. Unfortunately, its time as an Earth-mini just couldn’t be sustained.