"I think it's important to have a future that is inspiring and appealing. I just think there have to be reasons that you get up in the morning and you want to live. Like, why do you want to live? What's the point? What inspires you? What do you love about the future?" so says billionaire Tesla CEO Elon Musk in his 2017 TED talk.

For Musk, that means building a reality where humans live on multiple planets. "And if we're not out there, if the future does not include being out there among the stars and being a multiplanet species, I find that it's incredibly depressing if that's not the future that we're going to have," Musk says.