Thorne and his friends took this very seriously. You throw a billiard ball into the closed time light curve and it goes to the past, prevents itself from entering the closed timelight curve. That's Polchinsky's billiard ball paradox. And again, we're not doing many world's quantum mechanics or anything like that. We're trying our best to generalize the law of physics a little bit. The idea that you could in principle know the exact state of the universe at one moment in time and from that predict the future is called Laplace's demon.
Time! It doesn’t stop, psychological effects of being under lockdown notwithstanding. How we experience time depends on our situation, but time itself just marches forward. Unless, of course, it’s possible to travel to the past, as countless science-fiction scenarios have depicted. But does that really make sense? Couldn’t we then change the past, even so dramatically that our own existence would never have happened? In this solo podcast I talk about both the physics and fiction of time travel. I point out that it might be allowed by the laws of physics, and explain how that would work, but that we really don’t know. And I try to make sense of some of the less-sensible depictions of cinematic time travel. Coming up with a logical theory that could account for Back to the Future isn’t easy, but podcasting isn’t for the squeamish.
Support Mindscape on Patreon.
But wait, there’s more! I was contacted by Janna Levin, who we fondly remember from Episode 27. Janna moonlights as Chair and Director of Sciences at Pioneer Works, an institution dedicated to bringing together creative people in art and science. Like the rest of us, they’ve been looking for ways to offer more online content in these pandemic times, so we thought about ways to collaborate. Here’s what they came up with: artist Azikiwe Mohammed has created an animated video backdrop to this podcast episode. The visuals are trippy, colorful, and inspired by (without trying to directly illustrate) what I talk about in the episode. You can check out a brief write-up at the Pioneer Works site, or view the video directly below.
https://www.youtube.com/watch?v=kHy1j4LiyGQ
See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.