An unusual deposit spotted in one of Mars’s biggest volcanic regions might be the result of an eruption that popped the surface of the planet. If this is the case, it would mean Mars is still volcanically active today.

“Most of Mars’s activity was very early on – the first billion years or so of planetary evolution was an intense period of intense tectonic and volcanic activity,” says Jeffrey Andrews-Hanna at the University of Arizona. “The last 3 billion years on Mars has really been …