StarTalk Podcast: Cosmic Queries – Cosmic Grab Bag

Time Paradoxes

Time travel presents a fascinating conundrum, blending philosophical and scientific inquiries. Chuck Nice and Neil deGrasse Tyson explore the idea of stepping out of our timeline, which raises questions about predetermination and free will. Neil suggests that the inability to move back in time might indicate that we have free will, as stepping out would imply a predetermined timeline 1.

If you could step out of your timeline and then rejoin yourself, either in your future or in your past, that kind of would imply that your timeline is predetermined.

--- Neil deGrasse Tyson

They also discuss the causality paradox, where changing the past could prevent one's own existence, a concept Stephen Hawking proposed would never allow backward time travel 2.

   

Cosmic Views

Viewing Earth from distant planets offers a unique cosmic perspective. Neil deGrasse Tyson explains that if you were on a planet 2000 light years away with a powerful telescope, you could witness events like Roman battles as they happened, due to the time it takes light to travel 3. This concept extends to Superman's story, where Neil helped DC Comics determine the location of Krypton based on light travel time, suggesting Superman arrived on Earth through a wormhole 4.

If you are at the distance in light years from Earth, that corresponded to the time in the past that those Roman battles took place, you will see the Roman coliseum in real time.

--- Neil deGrasse Tyson

These discussions highlight how cosmic distances can serve as a lens to view historical events, offering a blend of science fiction and reality.