If you had to buy a new plane every time you flew somewhere, it would be incredibly expensive.

Even if there's a zombie apocalypse, you'll still be able to travel using the Tesla Supercharging system.

An asteroid or a supervolcano could certainly destroy us, but we also face risks the dinosaurs never saw: An engineered virus, nuclear war, inadvertent creation of a micro black hole, or some as-yet-unknown technology could spell the end of us.

As a child I would just question things.

We have this handy fusion reactor in the sky called the sun, you don't have to do anything, it just works. It shows up every day.

It would take six months to get to Mars if you go there slowly, with optimal energy cost. Then it would take eighteen months for the planets to realign. Then it would take six months to get back, though I can see getting the travel time down to three months pretty quickly if America has the will.

In order for us to have a future that's exciting and inspiring, it has to be one where we're a space-bearing civilization.