StarTalk Radio — "Our Burning Questions: Free Will Emergence"

Host: Neil deGrasse Tyson
Co-hosts: Chuck Nice (B), Gary O’Reilly (C)
Air Date: December 26, 2025

Episode Overview

This Special Edition of StarTalk Radio features a lively, year-end roundtable where the StarTalk team asks their own "burning questions," exploring hot science topics they personally find fascinating or unresolved. The conversation ranges from the essence of gravity and the strong nuclear force to emergent properties like free will, all infused with characteristic humor and approachable, insightful explanations. The central theme: where scientific laws, consciousness, and the universe’s mysteries cross paths.

Key Discussion Points and Insights

1. Experimenting With “Burning” Questions

• At the end of each year, the StarTalk team gets to ask their own questions (01:52) rather than fielding audience Cosmic Queries. This episode’s tradition is described as “naughty and nice,” with the group trading curiosity driven questions.
• The contest for hardest question is recalled: A Patreon user once posed a question about quarks so tough it stumped both Brian Greene and Brian Cox (02:49–03:09).

2. Favorite Non-Astrophysics Topic of the Year

• Neil deGrasse Tyson's pick: The interview with David Chalmers on consciousness (04:05).

  “I just like hearing an expert... so many people are opining on what consciousness is... and he just thought a lot about it.” (04:12)

3. Is Gravity Really a Force?

(05:00–20:45)

The Question

• Chuck Nice asks: Is gravity truly a force, or just the result of the bending of spacetime? If clocks tick more slowly closer to mass, does gravity exist as a force, or is it an illusion caused by curved time?

Neil's Explanation

• Equivalence Principle:
  • On a rocket accelerating at 1G, or standing on Earth, the inside experiment is indistinguishable—“experimentally identical.”
• Trajectory and Parabolic Motion:
  • Over short distances, projectiles approximate a parabola, but Earth's gravity points to its center—actually an ellipse (09:12).
• Gravity as Convenience:

  “It’s like saying, is a hot dog a sandwich—at one point, it’s just semantic.” (17:56)

• Indistinguishability:

  “To say, is gravity a force, or is it just curvature of space and time?…That distinction is immaterial.” (16:44)

• Memorable Moments:
  Comic banter about “violating gravity” and jumping in an elevator, plus a tongue-in-cheek exchange about pilot school voice and “raw dogging” satellites.

Notable Quote

“The universe is under no obligation to make sense to you.” – Neil deGrasse Tyson (37:25)

4. Cosmic Radiation and Airplane Safety

(24:44–35:16)

The Question

• Gary asks: Why did Airbus ground thousands of planes due to cosmic radiation and is this something all airlines should worry about?

Neil's Response

• Cosmic Rays originate from all over the galaxy, and although they’re everywhere, their effects are diffused by the atmosphere—still, they can affect sensitive digital/electrical systems at high altitudes.

• Software Redundancy:

  “If there’s any truly critical calculation… I would put a loop in there to do it three times… whichever two are the same, that’s the right answer.” (33:33)

• Critical Perspective:

  “Given how many planes are flying every day… and one plane uncontrollably loses altitude… you want to blame that on the universe?” (30:11)
  Implies human error/detectable issues are more likely than rare cosmic ray-induced failures.

• Humor:
  Chuck likens satellites exposed to radiation to “raw dogging the universe.” (34:06)

5. The Strong Nuclear Force, Quarks, and Gluons

(35:19–44:50)

The Question

• Chuck: What is the most straightforward explanation of the strong nuclear force—how does it hold quarks and nucleons together, and what’s a gluon anyway?

Neil’s Response

• The Four Fundamental Forces:
  • Gravity, electromagnetism, strong and weak nuclear forces.
  • Strong force “gets stronger as the distance separates”—like a rubber band (38:14)
  • Analogy:
    “You can ask, is there anything in your life where, if you increase the distance, they are attracted together more strongly? The answer is yes: a rubber band.” (38:14)
• Quarks and Gluons:
  • Quarks make up protons and neutrons; strong force holds them together, mediated by gluons (44:03).
  • Force Carrier Analogy:
    “Photon is the force carrier for electromagnetism; gluon is the carrier for the strong nuclear force.” (44:16)

Notable Quote

“Happy now? Yeah, it’s weird.” – Neil deGrasse Tyson (44:50)

6. How Do Physicists Choose the Right Equation?

(46:41–52:39)

The Question

• Producer Tamsin asks: When facing a physics problem, how do you determine which equations to use?

Neil’s Response

• Build a “Toolbox”:
  • You develop “an inventory of things that can happen in the universe and the equations that matter to it.” (47:04)
• Understanding Principles:
  • Not just formulas, but “a new understanding of the behavior of nature.” (49:35)
• Discovery as a Process:

  “Maybe the equation does not exist yet.” (51:15)

• Real-World Examples:
  • Superconductivity solved only after existing quantum physics was applied creatively.

7. Emergence and Free Will

(52:39–59:00)

The Question

• Lane (producer): Given that “emergence” (like fluid dynamics) lets us use macroscopic laws rather than track every particle, is free will also an emergent property? Is free will “just as real” as fluid dynamics? (53:26)

Neil’s and Chuck’s Response

• Emergence Defined:
  • Macroscopic descriptions (fluid dynamics, gas laws) can fully predict group behavior without tracking individuals.
• Free Will as Emergence:

  “Yeah, free will is an emergent feature of consciousness... Even if it’s not free will, if it feels like free will, it’s free will.” – Neil (55:03)

• Neuroscience Possibilities:
  • Future possibility: Measuring the “electrochemical state” of the brain might allow lawlike prediction of decisions, analogous to predicting gas behavior by pressure/temp (55:53).
• Implications for Society:
  • Behavioral prediction increases societal responsibility, especially regarding justice and mental health.

Notable Quote

“Time is defined to make motion look simple.” – Einstein, relayed by Neil (40:47)

8. The Sun’s Energy Trapped in Wood (and Food)

(59:44–62:14)

The Question

• Matt (editor): When we burn wood, are we actually releasing the Sun’s energy stored in trees?

Neil’s Response

• Yes – Photosynthesis:
  • “The energy of the Sun is contained within the trees... Plants use the Sun to build larger molecules with energy contained within.”
• Solar Powered:
  • All of our dietary energy traces back to the Sun, whether direct (plants) or indirect (animals eating plants).
• Humor:
  Paper burning as a “solar-powered” event; bemoaning how humans can’t digest cellulose but cows can (61:49).

Notable Quotes & Moments (with Timestamps)

• “If it looks like a duck, walks like a duck, quacks like a duck... it’s a duck.” – Neil (07:29)
• “[Physics] is not about the problem set. It’s about manipulating equations that exist only in the service of the problem you are reading.” – Neil (47:04)
• “The universe is under no obligation to make sense to you.” – Neil (37:25)
• “Even if it’s not free will, if it feels like free will, it’s free will.” – Neil (55:03)
• “Time is defined to make motion look simple.” – Einstein, via Neil (40:47)
• “Cannot steam clean with cold water.” – Chuck (58:30)
• Comic exchanges about pilots not really flying the plane (“I’m up here not doing a damn thing.” – Chuck, 33:03), satellites “raw dogging” the universe (34:06), and Slinky metaphors for weak springs (38:26).

Segment Timestamps

• [01:52] – StarTalk team annual burning questions tradition
• [04:05] – Favorite non-astro topic (consciousness interview)
• [05:00–20:45] – Gravity: force or illusion?
• [24:44–35:16] – Cosmic radiation and airplanes
• [35:19–44:50] – Strong nuclear force, quarks & gluons
• [46:41–52:39] – Choosing equations: physics “toolbox”
• [52:39–59:00] – Emergence, free will, and neuroscience
• [59:44–62:14] – Burning wood: the sun’s energy

Overall Tone

Lighthearted, humorous, “science for the curious,” with frequent analogies, geeky banter, and a commitment to explaining even tough physics concepts in plain language (“I'm a nut job. This is my problem. I'm a fricking nut job. But go ahead.” – Chuck, 43:30).

For New Listeners

This episode is a classic StarTalk blend: serious science you can grasp, comedic interludes, and deep philosophical questions—perfect for anyone curious about how physicists (and fun-loving cosmic nerds) actually think about the big stuff.

End note:
If you didn’t listen, you got laughter, learning, and a practical look at how scientists weigh the deepest questions—mixed with just enough “retro rocket” jokes to keep you smiling.