Would You Really Want to Know if You’re in a Simulation?

Neil deGrasse Tyson and comedian Paul Mercurio tackle listener questions in this Cosmic Queries edition of StarTalk, ranging from relativity and black holes to consciousness and simulated reality. The most striking segment addresses the nature of consciousness, where Tyson argues that stroke patients experiencing gradual loss of cognitive functions represent multiple partial deaths of the brain, suggesting death is simply the complete cessation of electrochemical activity with no afterlife—a claim he acknowledges is not comforting to religious believers. On the simulation hypothesis, both Tyson and Mercurio say they would demand to speak with the programmers to understand whether the universe is fully knowable through physics or contains zones of randomness where science loses utility. Tyson reveals that GPS satellites must pre-correct their time signals for Einstein's relativity because they experience time faster than we do on Earth's surface, demonstrating how abstract physics enables everyday technology. Addressing the Interstellar film, Tyson explains that observers near a black hole would see the rest of the universe unfold rapidly while appearing in slow motion to distant observers due to time dilation. On black holes and information theory, he describes how Hawking radiation creates particles that somehow preserve information about everything a black hole consumed, though he admits uncertainty about recovering complex data like DNA. The episode also covers whether Earth would maintain orbit if the sun became a black hole, the cosmic web structure of galaxy distribution, and how dementia affects memory storage. Throughout, Mercurio injects personal anecdotes about his mother's dementia and his career dating back to the original Daily Show with Craig Kilborn.

• Tyson argues that stroke-induced brain damage represents multiple partial deaths and suggests consciousness simply ceases at death with no afterlife, directly challenging religious narratives about what happens when we die.
• GPS satellites must pre-correct their transmitted time for Einstein's general relativity because they experience faster time in orbit than humans on Earth's surface due to gravitational time dilation effects.
• Black holes preserve information through Hawking radiation particle pairs that somehow remember everything the black hole consumed, though Tyson admits uncertainty about how complex information like DNA sequences could be recovered.
• Tyson states he would want to know if we live in a simulation and would demand answers from the programmers about whether the universe is fully knowable or contains zones where physics breaks down.
• Time dilation near black holes means observers on a planet close to the event horizon would see the rest of the universe age rapidly while appearing in slow motion to distant observers.
• Earth would continue orbiting normally if the sun became a black hole because black holes are not giant vacuum cleaners—extreme gravity only occurs very close to their tiny surface.
• The cosmic web describes how galaxies cluster along vast filaments of mostly dark matter with empty voids between, resembling a three-dimensional sponge rather than even distribution.