Elon Musk says the fastest way to make Mars livable is to nuke it

Billionaire Elon Musk wants to change the world. And with his hands in industries like rocket technology, electric cars, and solar energy, it seems like he could really do it.

But when Musk appeared on the "Late Show with Stephen Colbert" on Sept. 9, he said he's just "trying to do good things."

"You're trying to do good things, and you're a billionaire," Colbert said. "That seems a little bit like super hero or super villain - you have to choose one."

The matter was settled later in the interview when the conversation turned to Mars. It's no secret that Musk is hellbent on sending humans to the red planet - he says we could do it in the next 11 or 12 years with his rocket company SpaceX.

We'd have a lot of work to do after the first humans land there, though. "It is a fixer-upper of a planet," Musk said.

But with some hard work, Musk says we could transform Mars into an Earth-like planet. The average temperature on Mars is minus-80 degrees Fahrenheit, so the first step is to warm it up.

When Colbert asked him how we could warm up Mars, Musk had an interesting answer:

"The fast way is drop thermonuclear weapons over the poles," Musk said.

"You're a super villain," Colbert concluded.

The slow way (and safer way) to heat up Mars is to pump greenhouse gases, like methane and carbon dioxide, into its thin atmosphere. This process is called "terraforming" and it would take a long time - and a lot of resources.

In the meantime, humans would have to spend most of their time on Mars living inside domes to breathe and protect themselves from cosmic radiation. They'd also need to wear pressurized suits outside of their habitats, since the surface of Mars is almost a vacuum.

But if we pump enough greenhouse gases into the Martian atmosphere, just like on Earth, the gas will heat up the planet, melt some of its polar ice caps into oceans, beef up its thin atmosphere, and free chemicals in the soil. Those chemicals would break up into oxygen and allow plants to start growing. Plants would then create even more oxygen and make it possible for the planet to support animals and even humans.

So one day, if Musk has anything to say about it, we might walk around Mars sans space suit, farm Martian soils, and swim in Martian oceans. All thanks to nuclear weapons.