Noam Galai/Getty Images Bill Nye, above, said he's "open-minded but skeptical" about Elon Musk's plan to colonize Mars.

Bill Nye likes Mars as much as the next guy ― more, probably, since the Science Guy also heads up The Planetary Society, a Pasadena, California-based nonprofit that pushes exploration of the solar system.

But Nye isn’t totally sold on SpaceX CEO Elon Musk’s bold new plan to colonize Mars.

Under the plan, which Musk detailed Tuesday at a major astronautics conference in Guadalajara, Mexico, SpaceX will build a fleet of vast spaceships and use them to ferry wave upon wave of humans to the red planet. The company aims to send the first humans to Mars in 2025.

“I’m open-minded but skeptical that anyone actually wants to live out his or her life on Mars any more than anyone wants to colonize Antarctica,” Nye told The Huffington Post in an email. “Mars is an exotic place and in some ways very romantic. But it’s cold, barren and you can’t even breathe.”

And the cost for getting to Mars will be astronomical. Musk anticipates charging folks about $200,000 apiece for a trip to the red planet ― and that’s after the price comes down.

Musk has long considered the colonization of other planets a life-or-death imperative, given the existential threats to life on Earth posed by runaway climate change, killer asteroids and the like.

“Ultimately, the thing that is super-important in the grand scale of history is, are we on a path to becoming a multi-planet species or not?” Musk said in 2011 (and has been saying ever since). “If we’re not, that’s not a very bright future. We’ll just be hanging out on Earth until some eventual calamity claims us.”

Nye, who was on hand in Guadalajara for Musk’s well-attended presentation, is known for climate activism as well as for his enthusiasm for space exploration.

But establishing a Mars colony clearly isn’t his first priority.

“I very much hope we conduct a thorough, careful search for life on Mars before we consider landing dozens of tons of people and cargo,” he told HuffPost.

That search is already underway, of course. For decades now, NASA has been sending landers and rovers to Mars ― and the space agency has its own plan to send astronauts there sometime in the 2030s. By then, Musk’s colonists might have been living on Mars for years.

In any case, Nye praised SpaceX for changing how the world thinks about spaceflight. “Watching the crowd go absolutely wild today,” he added, “tells me that the best is yet ahead for space exploration.”