What happened to Mars?
It’s likely that billions of years ago, Mars had entire oceans on its surface. Conditions were good for life to develop and at the time, it was even a more habitable planet than Earth.
So what happened?
Recently NASA revealed that they’d discovered liquid water still runs in small amounts on Mars, but its no more than an implication of what was and could’ve been. Today Mars is largely a barren planet which seems to be more tomb than home.
NASA’s MAVEN mission, luckily, was able to figure it out.
It turns out, Mars’ atmosphere (what little’s left) is being torn apart by something known as the “solar wind”. This is a stream of charged particles that explode out of the Sun into space. Little by little, these particles are able to rip off bits of Mars’ atmosphere. The rate this happens, as observed by MAVEN, matches up with the general era in which we think Mars’ atmosphere still flourished.
When a planet doesn’t have an atmosphere, the pressure and heat needed to keep water liquid is mostly gone. Some of the water evaporated into the remaining atmosphere (most of which was then stripped away into space) and some froze.
So why did this happen to Mars? Could it happen to Earth?
Yes and no. The reason why it happened to Mars is because it’s such a small planet. Smaller things cool down quicker. I challenge you to go get a large coffee and a small coffee and wait to see which one cools faster.
You see, Mars and Earth both have iron cores. When the planets formed out of molten conglomerates in space, these iron cores were hot, even after the outer crust of the planets cooled against the vacuum of space.
A rapidly spinning, molten iron core (for those physicists among us) already know: this is all you need to generate a magnetic field!
The Sun’s solar wind, as it happens, is subject to magnetism since it’s made up of charged particles. All you need, therefore, to protect yourself from the solar wind, is a magnetic field. The charged particles will be stopped by the field, travel up and down to the planet’s magnetic poles where they’ll discharge in a flash of light known as a borealis:
So there you have it: the Northern Lights killed Mars.
… well not really but it’s all connected in a wonderful, interesting way.
Earth is safe from such a fate so long as we can protect our atmosphere from the solar wind, and even then the stripping away of the atmosphere wouldn’t happen overnight.
(Image credit: NASA)