F or a long time, scientists believed that Mars was not only red, but dead. This didn’t make the planet any less interesting, since there’s F evidence of rivers flowing into lakes and the potential that Mars may have once harboured life. But just one look at this small, ghostly world appears to suggest that it’s a largely dry and dusty husk. Not much, it has been assumed, has happened on Earth’s neighbour for the past 3 billion years. Or so it was thought. “The geological history of Mars was understood to be very simple,” says Adrien Broquet, a postdoctoral research associate at the University of Arizona’s Lunar and Planetary Laboratory. “The planet formed at the same time as Earth some 4.5 billion years ago, and there was a tremendous amount of volcanism about 3 to 4 billion years ago. Enormous volcanic activity formed the largest volcanoes in the Solar System, for example Olympus Mons. Since then, Mars was understood to have slowly cooled down, with less and less volcanic activity.”
After 2018, the scientific perception of Mars began to change. That year, NASA launched the InSight mission, which sent a lander to the Red Planet to investigate its interior structure and composition. By studying Mars’ crust, mantle and core, the mission sought to get to the bottom of how rocky planets formed in our inner Solar System while also determining the level of tectonic activity on
