The Sun Peels Off Mars’ Atmosphere

Once there was an abundance of liquid water on the Red Planet. NASA’s MAVEN is investigating why the planet is bone-dry today.

Earth’s bone-dry neighbour, Mars, was probably soaking wet and included rivers, lakes, and perhaps even oceans 4 billion years ago. Everything wrapped in a dense atmosphere that allowed the liquid water to remain. Since then, the atmosphere has become much thinner, i.e. only 1/100 of Earth’s.

So far, astronomers have not known why the atmosphere disappeared, but now, they think the Sun caused the drought, as solar wind particles blew away the atmosphere.

NASA’s MAVEN probe is orbiting the planet to study the atmosphere. Existing measurements show that the Martian atmosphere is losing about 100 g of gases per second. The solar wind produces an electric field that forces charged atoms on the edge of the atmosphere into space.