StarTalk Radio: Cosmic Queries – Expanding Bubble Universes

Host: Neil deGrasse Tyson
Co-host: Chuck Nice
Date: January 13, 2026

Episode Overview

This episode of StarTalk Radio is a Cosmic Queries "Grab Bag" edition, where Neil deGrasse Tyson and comedian Chuck Nice tackle listener-submitted questions spanning black holes, the nature of the sun, interstellar travel, the Big Bang, relativity, quantum gravity, warp drives, and multiverse theory. The episode blends robust explanations, speculative science, sharp wit, and pop culture references, making for an entertaining yet insightful journey through some of the cosmos’s biggest open questions.

Key Discussion Points & Insights

1. Firing Nukes at the Sun & Fusion vs. Fission

Timestamps: 02:10 – 12:33

• Listener Q: Did the science fiction of "Sunshine" (reviving the Sun with Earth's nuclear material) get anything right?
• Explained Concepts:
  • Fusion (what powers the Sun) vs. fission (what powers most of our nukes).
  • Throwing all of Earth’s nukes into the Sun would be “like throwing spitballs”—utterly insignificant to the Sun’s scale.
  • Practical way to prolong the Sun's life: stir up hydrogen through induced convection (not possible with today’s tech).
  • Approaching the Sun requires shielding and a clever heat management strategy (“rotisserie” method).
  • Notable Quote:
    "You want to try to start the sun with nuclear fission? It's like trying to jumpstart a jet engine with a kitchen match." – Neil deGrasse Tyson (04:44)
  • Highest melting point element: carbon (diamonds).
• Memorable Moment: Jokes about “diamond spaceships” piloted by hip-hop stars and Elizabeth Taylor.

2. Generational Spaceflight & Technological Leapfrogging

Timestamps: 12:33 – 16:38

• Listener Q: If we send a generation ship to another star, will it be overtaken by faster ships later?
• Key Points:
  • Yes, future advances might overtake earlier missions—unless we develop “warp drives” and can dock/rescue earlier travelers.
  • Sometimes, it’s preferable to fix problems on Earth rather than embark on risky, interstellar journeys.
  • Notable Quote:
    "Whatever was the problem with Earth that you're trying to escape? Just fix it." – Chuck Nice (15:04)
  • If a planet is habitable, it probably has life already, possibly dangerous and unfamiliar.

3. Visualizing the Big Bang for Children

Timestamps: 18:19 – 19:56

• Listener Q: How should we visualize the Big Bang?
• Explanation:
  • The “balloon” analogy: The universe’s expansion is like inflating a balloon with galaxies drawn on its surface.
  • Emphasized that the Big Bang isn’t an explosion in space, but of space.
  • Notable Quote:
    "Our three spatial dimensions are flattened into the surface of a balloon, and the time dimension is the distance from the tie." – Neil deGrasse Tyson (19:20)

4. Relativity: Shrinking, Mass, and Time at High Speeds

Timestamps: 20:55 – 23:17

• Listener Q: Does moving near light speed make you infinitely small? Do you become light?
• Explained Concepts:
  • Length contraction only in direction of motion; mass increases, time slows from outside observer's point of view.
  • No, you don’t become light; only massless particles (“photons”).
  • Tidal forces inside black holes explained (“spaghettification”).
  • Notable Quote:
    "You don't shrink, but you will be measured to get sort of thinner front to back as your speed increases." – Chuck Nice (21:19)
  • Humorous segment about noble photons landing on butts vs. detectors.

5. Black Hole Slingshots and Speed Limits

Timestamps: 25:05 – 30:18

• Listener Q: Can you use a gravitational slingshot around a black hole to exceed light speed?
• Explained Concepts:
  • Gravitational slingshot relies on stealing momentum from moving objects (e.g., planets), not black holes per se.
  • Nothing with mass can reach or exceed speed of light.
  • Getting close to a supermassive black hole’s event horizon won’t rip you apart—yet.
  • Notable Quote:
    "If you're made of material substance, you can't go the speed of light. The slingshot just adds energy, not enough to break the rules." – Neil deGrasse Tyson (29:36)

6. Is Our Universe Inside a Black Hole?

Timestamps: 30:23 – 32:15

• Listener Q: Does the expanding universe contradict the 'universe in a black hole' theory?
• Physicist’s take:
  • Not all black holes are currently "feeding," so lack of visible infall doesn’t rule it out.
  • Black hole evaporation via Hawking Radiation would take unfathomably long for a universe-sized black hole.

7. Warp Drives, Subluminal Travel, and Acceleration

Timestamps: 32:38 – 34:15

• Listener Q: On the practicality and physics of sub-light ("subluminal") warp drives.
• Points Made:
  • Warp drives theoretically manipulate space-time, could go slower OR faster than light.
  • Notable Quote:
    "The Alcubierre drive is a way to go faster than light, but there's nothing in principle preventing you from dialing it down and going slower." – Neil deGrasse Tyson (33:54)

8. Nature of the Graviton & Quantum Gravity

Timestamps: 35:37 – 39:12

• Listener Q: If the graviton is not quantum, could black holes be gravitons in higher dimensions?
• Explanation:
  • Gravity as spacetime curvature (Einstein) vs. force carrier particle (graviton).
  • Gravitational waves have been detected, but gravitons remain hypothetical.
  • Skepticism about equating black holes with gravitons.
  • Chuck: "It’s usually a mistake to use something you don’t understand to explain something you don’t understand."

9. Bubble Universes & Multiverse Collisions

Timestamps: 39:50 – 42:04

• Listener Q: As our universe/bubble expands, can it merge with another bubble universe? What might happen?
• Insight:
  • Different bubbles may have different laws of physics—could be catastrophic for anything crossing over.
  • Notable Quote:
    "If you visit another universe bubble where the electron’s charge is different, you could just explode or collapse." – Neil deGrasse Tyson (40:10)
  • Fun speculation: could dark matter or dark energy be signatures of another universe passing through?

10. Simulation Theory & Gravitational Time Dilation

Timestamps: 43:13 – 45:11

• Listener Q: Is time dilation near gravity like a video game’s frame-rate drop in complex regions—evidence we’re in a simulation?
• Take: It’s a fun metaphor. In simulation theory, you’d expect only observed portions of the universe to be fully rendered.

11. Black Hole Information Paradoxes

Timestamps: 45:12 – 47:23

• Listener Q: Could a quantum computer/AI be sent into a black hole to retrieve information about quantum gravity?
• Answer: Once past the event horizon, information can’t be retrieved—only Hawking Radiation leaks it out gradually in an unrecoverable way.

12. Tachyons and Hypothetical Faster-Than-Light Particles

Timestamps: 47:24 – 51:12

• Listener Q: If we could accelerate particles faster than light, would they travel backward in time?
• Explanation:
  • Tachyons are hypothetical particles that would travel backward in time; never observed.
  • “You can approach the speed of light but can’t reach or exceed it if you have mass.”
• Notable Quote:
  "If you could, the particles would go backwards in time. That’s tachyons—but we’ve never found them." – Neil deGrasse Tyson (49:38)
• Humorous aside on diamonds vs. cubic zirconia as marriage advice—classic Chuck Nice.

Notable Quotes & Memorable Moments

• Neil deGrasse Tyson on photon travel:
  "The photon is created in an atom and is absorbed wherever it’s headed… instantly—to it." (22:45)
• Chuck Nice on fixing problems rather than fleeing Earth:
  "Just fix it. How about that?" (15:06)
• On warp drives and Star Trek:
  "Even in Star Trek, they have warp one through nine. Warp factor one is the speed of light." – Neil deGrasse Tyson (34:15)
• On quantum computers in black holes:
  "It ain't coming out… There's the Hawking radiation, but it pulls it out as a striptease." – Chuck Nice (47:03)
• On science fiction universes:
  "If you visit another universe bubble where the electron’s charge is different, you could just explode or collapse." – Neil deGrasse Tyson (40:10)

Conclusion

This episode offers a whirlwind tour of cosmic riddles posed by curious listeners and answered with both rigor and comedic flair. Listeners are reminded of the scale and mysteries of the cosmos while being entertained by the hosts' banter—even as questions brush up against the limits of current physics. The grab bag format covers a vast scope, leaving one both more informed and even more in awe of the universe.

Listener encouragement from Neil: "As long as you keep sending them, we’ll keep doing it." (51:28)

Keep Looking Up!