Is Time Travel, Especially Into the Past Possible? | Matt Szydagis | TEDxSchenectady
23:45
Fermi's Paradox and the Psychology of Galactic Empires | Matthew O´Dowd | TEDxTUWien
22:31
Filling the Big Gap in Einstein’s Theory | Paul Steinhardt | TEDxCLESalon
15:01
¿Te imaginas como sería un viaje interestelar? | Ryan Weed | TEDxDanubia
17:42
A Theory You've Never Heard Of | Michael Robinson | TEDxUniversityofHartford
17:39
A take on time travel paradoxes | Paul Bunnell | TEDxEmbryRiddlePrescott
22:52
8 ways the world could suddenly end: Stephen Petranek at TEDxMidwest
16:06
Cosmology and the arrow of time: Sean Carroll at TEDxCaltech
14:59