Lawrence Krauss is a busy man. A theoretical physicist and cosmologist at Arizona State University, Krauss has studied the universe, served on the science policy committee for Barack Obama's first presidential campaign, and crossed paths with intellectuals like Stephen Hawking and Christopher Hitchens. He has authored several books, including The Physics of Star Trek. In February 2014, Krauss took part in an American Association for the Advancement of Science symposium titled Where's My Flying Car? Science, Science Fiction, and a Changing Vision of the Future.

We caught up with him in the recent past, to talk with him about the future.

So, where is my flying car?

Your flying car is still in the dreams of people 50 years ago. You can feel bad that we don't have flying cars, that we're not living in hotels in space, but the real world intervenes. Certain [technological innovations] are just a lot harder, a lot more expensive.

At the same time, there's a flipside: The real things that have happened are much more interesting. The Internet is a clear example of how our lives have changed in ways we couldn't have imagined: a distributed information source, which is invisible to everyone, where you can access anything, and it's distributed throughout the whole world. Basically, communication is instantaneous.

When it comes to the things that people really want in science fiction—like space travel—the simplest things end up causing them not to happen. Humans are 100-pound bags of water, built to live on Earth.

We hoped for flying cars and got the Internet instead. What's to blame for the difference between our hopes and the reality we end up with instead?

I would say [innovations] almost never come from predictable places. If innovations were predictable, they wouldn't be discoveries. When people extrapolate into the future, they extrapolate [from] the known present. If I knew what the next big thing was, I'd be doing it now.

What have we done to the world? Climate change. Overpopulation. Global inequity. Perhaps a virus we set loose from the animal world by displacing so many exotic species, which could wipe us all out. These all either seem to be here already or looming in our near future.

The virus thing: I wouldn't stay up overnight on it. We're pretty robust; we've survived for four and a half million years.

So what does the future hold?

It looks like we're destroying the world as we know it. We certainly are entering Earth 2.0. But where that will go is not clear.

Are you hopeful for the future?

It depends on the day. I'm not very hopeful that humanity can act en masse to address what are now truly global problems that require a new way of thinking. As Einstein said when nuclear weapons were created: "Everything's changed save the way we think."

I think we need to change the way we think to address these global problems. Will it happen? Maybe kicking and screaming. My friend, the writer Cormac McCarthy, told me once: "I'm a pessimist, but that's no reason to be gloomy." In a sense, that's my attitude.

Five hundred years from now, will we be living on Mars?

Maybe. If we do space travel, it will tend to be one-way trips. Throughout human history, people have done these ridiculously difficult one-way voyages for one reason: because where they lived was so awful they were willing to get on a little wooden vessel that might sink and go across an ocean to some unknown place that they would probably never return from because it was so crummy where they were.

Maybe we'll do that for ourselves. We'll make the world so miserable that living in some harsh environment on Mars might seem attractive.