Leave it to Elon Musk to get us all heated up about terraforming Mars. The billionaire entrepreneur had the honor of appearing during the first week of Stephen Colbert's new reign as the host of "The Tonight Show," with the pair chatting about everything from electric cars to space exploration. When Musk, who has his eyes set on spearheading the first human colonies on Mars, was asked by Colbert what it would take to turn the red planet into something more hospitable, the 44-year-old returned a surprising answer.

"Drop thermonuclear weapons over the poles," he said.

While it may sound like something, as Colbert alludes, that a supervillain would do, there's some actual science behind this idea. Mars itself at one point was a very lush and warm world not unlike our own Earth. Active volcanoes played a vital role in atmospheric recycling (as they do on Earth) and a hot core helped maintain a magnetic field to protect from solar winds. At some point, the core cooled, its magnetic field all but disappeared, the atmosphere was thinned away, and the entire planet began to freeze. Mars, once perhaps a blue and green marble like our own Earth, became a dry husk.

By detonating thermonuclear weapons over the poles, humanity could effectively provide the nudge that's needed to perhaps trigger a runaway greenhouse effect on Mars. The bombs would release heat, which in turn would melt the carbon dioxide frozen at the poles and, in theory, help to immediately thicken Mars' thin atmosphere. As sunlight is trapped by the C02, the temperature would rise, more ice would melt, and so on.

As one might expect, not all scientists agree with this quick and dirty method for terraforming Mars. For one, we would irrevocably change a large portion of the surface of the planet and two, we might actually cause the opposite effect of what we're looking for.

Michael Mann, a professor and director of the Earth System Science Center at Penn State University, told U.S. News that nuking the poles could create what's called a nuclear winter. "Wherein you generate so much dust and particles that they literally block out a significant portion of the incoming sunlight, cooling down the planet,” he said.

So if nukes are out, what other ways might we turn Mars into a habitable neighbor? Below are five real possibilities that might sound too incredible to be true, but may one day punch our ticket to a vacation home on the red planet.

Terraform MarsArtist's conception of the process of terraforming Mars. (Photo: Daein Ballard/WikiMedia)

1. Giant orbital mirrors

Straight out of science fiction, one of the more common terraforming ideas involves the construction of a giant array of Mylar mirrors to reflect the sun's heat towards Mars' poles. How big are we talking? Roughly 155 miles across and covering an area larger than Lake Michigan. Since this entire reflector would weigh more than 200,000 tons, it likely would have to be constructed in space — a massive engineering undertaking that boggles the mind. Nonetheless, once in place at an altitude of nearly 133,000 miles above the surface, the energy directed back on Mars would be enough to vaporize the trapped CO2 and potentially trigger a greenhouse effect.

2. Direct a giant asteroid towards the planet

It's widely believed that asteroids and comets played an instrumental role in forming Mars' previously warm and wet climate. Assuming we could capture and/or direct these giant bodies moving through our solar system, it's possible we could angle them to enter Mars' orbit and then burn up in the atmosphere, releasing massive quantities of greenhouse gases. Like nuclear weapons, the other more destructive method would be to have several 10-billion-ton asteroids smack directly into the planet (equivalent to 70,000 one-megaton hydrogen bombs). Just one would result in a global temperature spike of 5 F.

3. Cover the poles in dark dust

Like wearing dark clothing on a cold day to capture the sun's heat, another proposal for warming up Mars involves covering the poles in a layer of dark dust. And where would we get this material? By mining Mars' two moons — Phobos and Deimos — two of the darkest bodies in our solar system. According to Carl Sagan, the amount of dark dust would need to average nearly 3 feet and, unbelievably, be replaced each year due to the planet's frequent dust storms. That giant 155-mile-long orbital mirror suddenly sounds a lot more practical, right?

4. Let human-engineered microbes do all the work

Instead of lassoing an asteroid or spending way too much time mining Phobos, the best option might be to simply engineer microorganisms to do all the terraforming of Mars for us. While the red planet's current habitat is (maybe) a death sentence for life, the Pentagon’s Defense Advanced Research Projects Agency (DARPA) revealed earlier this year that they might be able to come up with something that could hack it. The agency has designed what it called the "Google Maps of genomes" that will allow them to build new life from the genes of different microorganisms. This could result in genetically engineered plants, algae and other organisms that could survive, thrive and maybe even heat up Mars.

"For the first time, we have the technological toolkit to transform not just hostile places here on Earth, but to go into space not just to visit, but to stay,” DARPA's Alicia Jackson said.

5. Bring the Industrial Revolution to Mars

Faced with our own challenges from global warming on Earth thanks to factories spewing out greenhouse gases, could something similar work for Mars? That's the idea behind the plan to build factories powered by renewable energy on the red planet with the sole purpose of releasing methane, carbon dioxide, CFCs, water vapor and other greenhouse gases into the atmosphere. While this process would take centuries to warm Mars, it would allow humans plenty of time to settle the planet and help prepare it for its future role as a "new Earth."

Regardless of if these methods are used in tandem or alone to terraform Mars, humanity will still have to figure out way to kickstart the planet's core to create a magnetic field that keeps these changes permanent. Thankfully, any atmosphere created by humans would take thousands of years to dissipate from solar winds — leaving us plenty of time to come up with something crazy like the above to finally call Mars home.

Update: Elon Musk would like everyone to know, he's not actually pushing to nuke Mars.