MAVEN Uncovers How Mars Lost Its Atmosphere

Imagine Mars used to have a thick blanket of air like Earth.

But now, it's thin.

Scientists used a space machine called MAVEN to figure out why.

They found that tiny particles from the sun, like a cosmic wind, hit the air at the top of Mars and knocked the air molecules away, like a cannonball splashing in a pool.

This is called sputtering.

This process was much stronger long ago when the sun was more active.

The sputtering happened four times faster than thought, so Mars's air and water disappeared.