StarTalk Radio: Cosmic Queries – Renaming Time
Host: Neil deGrasse Tyson
Co-Host: Chuck Nice
Release Date: June 10, 2025

Science, pop culture, and comedy collide in this engaging episode of StarTalk Radio, where Neil deGrasse Tyson and his co-host Chuck Nice delve into a series of listener-submitted questions. Titled "Renaming Time," this episode explores complex scientific concepts with humor and clarity, making intricate topics accessible to all listeners.

1. The Relationship Between Time and Motion

[02:13] Listener Eric44 poses the philosophical question: "All motion requires time, but does all time include motion?"

Chuck Nice responds thoughtfully:

"I would say the measurement of time requires not only motion, but something that repeats periodically. Have you ever measured time with something that did not repeat periodically? The answer is no."
— Chuck Nice [02:35]

Discussion Highlights:

• Repeatability as a Measure of Time: Chuck emphasizes that our ability to measure time hinges on periodic events (e.g., seconds, days), suggesting that without repetitive motion, time lacks a coherent measure.
• Relativity of Event Sequence: They touch upon how, in different reference frames, the sequence of events can vary, aligning with Einstein’s theory of relativity.
• Space Without Time: The conversation briefly explores the notion that space can exist independently of time, illustrating this with humorous banter about personal presence.

2. Recommended Reading for Young Minds

[04:21] Listener Maurice Backer (Eljada) from the Netherlands asks: "What is the one book that every 12-year-old should read?"

Chuck Nice recommends his own works:

"My book 'Astrophysics for People in a Hurry' has a young people's version called 'Astrophysics for Young People in a Hurry.' And for pure fun, there's 'Merlin's Tour of the Universe,' a Q&A illustrated by my brother."
— Chuck Nice [06:07]

Discussion Highlights:

• Astrophysics for Young People: Tailored for ages 8 to 12, this book combines scientific insight with relatable experiences, aiming to inspire the "tween" generation.
• Merlin's Tour of the Universe: A creative, illustrated Q&A format that makes learning about the cosmos enjoyable.
• Humorous Interaction: Neil and Chuck engage in light-hearted conversation about pronunciation and the maturity of young listeners, adding a personable touch to the recommendation.

3. Visualizing the Expanding Universe

[08:19] Listener Andrew Bowen questions: "What does it look like when I'm facing back at us versus facing outward ahead in the expanding universe?"

Chuck Nice provides an insightful explanation:

"It looks just like it does here and now. We are at the horizon of anybody who’s at our horizon."
— Chuck Nice [09:17]

Discussion Highlights:

• Consistent Appearance from Any Horizon: The universe appears uniform from any point at the event horizon, similar to being at the center of an infinite ocean.
• Cosmic Microwave Background: They discuss the implications of the cosmic microwave background disappearing, leading to a theoretical edge of the universe devoid of matter.
• Future Implications: The conversation explores the eventual expansion of the universe beyond observable galaxies, pondering the infinite nature of the cosmos.

4. Black Hole Singularities and the Limits of General Relativity

[19:00] Listener James H. English from Greenland/Odessa inquires: "What does it mean to say singularities at the heart of a black hole may just be mathematical artifacts?"

Chuck Nice delves into the complexities:

"When we talk about the size of a black hole, functionally we're talking about the size of the event horizon. Inside the event horizon, all bets are off... The general theory of relativity has limits to its applicability."
— Chuck Nice [19:25]

Discussion Highlights:

• Singularities as Mathematical Concepts: They discuss how singularities represent points where our current understanding of physics breaks down, indicating the need for a unified theory that reconciles general relativity with quantum mechanics.
• Quantum Physics Frontier: The conversation touches on ongoing efforts by physicists and string theorists to address these limitations and better understand the true nature of singularities.
• Humorous Analogies: Chuck humorously references algebraic errors ("dividing by zero") to illustrate the undefined nature of singularities.

5. The Science of Transparency and Light

[21:52] Listener Michael Trilling asks: "How can light travel through some materials but not others? What makes something transparent at an atomic level?"

Chuck Nice offers a concise explanation:

"Transparent media have nothing to change the pathway of the light through the medium, so it maintains a straight direction... In contrast, translucent materials like frosted glass disperse the light, preventing a coherent image."
— Chuck Nice [22:13]

Discussion Highlights:

• Transparency vs. Translucency: The duo explains how the atomic structure of materials affects light transmission, differentiating between materials that are fully transparent and those that scatter light.
• Role of Lenses and Refraction: They discuss how lenses manipulate photon pathways to reconstruct images, highlighting the physics behind everyday optics.
• Diamonds and Light Refraction: Chuck elaborates on why diamonds are prized for their ability to refract light, creating their characteristic sparkle.

6. Mining the Moon and Gravitational Effects

[23:57] Listener Alex Romillion from Northeast England raises concerns: "Wouldn't mining the moon and transferring its mass to Earth weaken the tides over time?"

Chuck Nice reassures listeners:

"If you mined 100% of the moon and brought it back to Earth, Earth would weigh only slightly more—about 1% more mass. This change is negligible compared to daily fluctuations like going to the bathroom."
— Chuck Nice [25:36]

Discussion Highlights:

• Mass Transfer Impact: They examine the relative mass of the Moon compared to Earth, concluding that even significant mass transfer would have minimal effects on Earth's tides.
• Practical Implications: The conversation humorously downplays the concern by comparing it to everyday weight fluctuations, emphasizing the impracticality of altering the Moon’s mass substantially.

7. The Feasibility of Creating Wormholes

[29:03] Listener Zach from Moonsville, New York is curious: "What is keeping us from taking the mathematics of wormholes from paper and applying them to the physical world?"

Chuck Nice explains the scientific barriers:

"We need matter with negative gravity to create and stabilize wormholes, something we currently don’t have. While dark energy presents a form of negative pressure, harnessing it for wormholes remains speculative."
— Chuck Nice [30:36]

Discussion Highlights:

• Negative Matter Requirement: The necessity of negative gravity substances for wormhole creation is emphasized, highlighting a significant hurdle in making theoretical constructs a reality.
• Role of Dark Energy: They explore the potential of dark energy as a candidate but acknowledge the lack of understanding and technology to utilize it effectively.
• Imagining Practical Applications: The conversation takes a creative turn as they humorously envision everyday uses of wormholes, such as instant grocery restocking.

8. How Massless Photons Carry Information

[33:30] Listener James Liggett from Midland, Texas questions: "Since photons have no mass, how do they carry the image of their source to a telescope or an eyeball?"

Chuck Nice provides a detailed response:

"A single photon contains no image information, but an ensemble of photons can reconstruct an image through lenses that focus light from different points of the source onto a detector."
— Chuck Nice [34:54]

Discussion Highlights:

• Photon Ensembles vs. Individual Photons: They clarify that while single photons carry energy, it’s the collective behavior of many photons that forms a coherent image.
• Optical Mechanics: The role of lenses in directing photons to specific areas of the retina or sensors is explained, illustrating the physical process behind vision and imaging.
• Educational Insight: This segment offers listeners a deeper understanding of how our eyes and telescopes translate massless particles into the rich images we perceive.

9. The Universe Inside a Black Hole

[36:35] Listener Alan from Italy muses: "If our universe is located inside a black hole, where is the singularity? Why don't we see other black holes taking over our universe?"

Chuck Nice tackles the intriguing hypothesis:

"Our universe may share some equations with black holes, such as having an event horizon, but each black hole contains a separate universe through higher dimensions, preventing overlap."
— Chuck Nice [37:55]

Discussion Highlights:

• Analogous Equations: The conversation explores how certain mathematical similarities between black holes and the universe suggest a possible connection, yet distinct differences prevent direct comparison.
• Higher Dimensions: They discuss the role of higher dimensions in accommodating multiple universes within black holes without physical interference.
• Holographic Principle: The idea that our universe might reside within a black hole's holographic information is touched upon, sparking ambition for future theoretical explorations.

Conclusion

Neil deGrasse Tyson and Chuck Nice wrap up the episode with reflections on the diverse and thought-provoking questions. Their blend of scientific rigor and playful interaction ensures that listeners not only gain a deeper understanding of complex topics but also enjoy the journey through cosmic queries.

Notable Quotes:

• Chuck Nice on Time and Motion:

  "All you'd be able to do in your own reference frame is sequence events. This came before that. Before that."
  — Chuck Nice [03:14]

• Neil deGrasse Tyson on Wormholes:

  "You just walk through a portal and you're there. That’s so cool."
  — Neil deGrasse Tyson [32:14]

• Chuck Nice on Transparency:

  "Light travels slowest in a diamond, which helps it internally reflect so that when light comes in from one direction, it pops out a different direction."
  — Chuck Nice [23:08]

Key Takeaways:

1. Time and Motion: Time measurement relies on periodic motion, making the concept of time intrinsically linked to repetitive events.
2. Youth Education: Accessible and engaging scientific literature can inspire young minds, fostering a lifelong interest in the cosmos.
3. Universal Symmetry: The universe appears consistent from any vantage point at the event horizon, reflecting its infinite and expanding nature.
4. Black Hole Mysteries: Singularities challenge our current understanding, highlighting the need for advanced theories that bridge general relativity and quantum mechanics.
5. Optics and Light: The atomic structure of materials determines their transparency, with practical applications in lenses and modern technology.
6. Moon Mining Realities: Mass transfer from the Moon to Earth would have negligible effects on tidal forces, mitigating concerns over such large-scale endeavors.
7. Wormhole Potential: Theoretical physics outlines the possibilities of wormholes, but practical implementation remains elusive without understanding negative gravity.
8. Photon Imaging: While individual photons lack image information, their collective behavior underpins the visual information processed by our eyes and instruments.
9. Universe as a Black Hole: Speculative theories suggest our universe might reside within a black hole's event horizon, though higher dimensions offer explanations for coexistence with other universes.

Join Neil deGrasse Tyson and Chuck Nice in future episodes as they continue to unravel the mysteries of the universe with curiosity, humor, and scientific insight.