The incredible video above shows how solar winds from the sun have stripped away Mars’ atmosphere, and along with it, the planet’s ability to sustain the vast oceans that geologists believe used to be there.
A solar wind is a stream of particles—mostly protons and electrons—rocketing out of the sun at about a million miles per hour. It carries with it a magnetic field that can produce an electric field, causing ions, or electrically charged gas atoms, to shoot off the planet and out into space. It’s like electromagnetic atmosphere erosion.
Figuring out where the atmosphere and oceans went was the mission of NASA’s Mars Atmosphere and Volatile Evolution, or “MAVEN,” satellite, which launched toward the red planet in 2013. Since then, MAVEN has been watching solar winds continue to do their thing. NASA estimates they strip away about 100 grams (or about a quarter pound) of gas a day, and that adds up over time. And because scientists observed that increased solar activity results in more atmospheric erosion, they figure that billions of years ago, when the solar system was more active, the loss rate must have been much higher.
In case you’re wondering why the same thing hasn’t happened on Earth, don’t worry. We have something Mars doesn’t have: our own magnetic field that shields us from solar wind damage.