Podcast Summary

Podcast: New Books Network
Host: Gregory McNiff
Guest: Marcus Chown
Book: A Crack in Everything: How Black Holes Came in from the Cold and Took Cosmic Centre Stage (Apollo, 2025)
Date: November 7, 2025

Episode Overview

This episode features an in-depth conversation between Gregory McNiff and Marcus Chown, author of "A Crack in Everything," a book charting black holes’ journey from being theoretical impossibilities to cosmic VIPs. The discussion covers not only the scientific evolution of our understanding of black holes but also the human stories, scientific rivalries, and paradigm-shattering discoveries behind this cosmic journey. Chown’s clarity and storytelling, as well as his firsthand interviews with pioneering scientists, shine through as he explains why black holes have become central to our understanding of the universe.

Key Discussion Points & Insights

1. Why Write About Black Holes? (03:23)

• Origin of Chown’s fascination: Inspired at age 12 by Paul Murdin describing Cygnus X-1’s discovery.
• Audience goal: Chown writes for "anybody," aiming for accessibility for non-scientists as well as experts.
  • "If [my wife’s] eyes glaze over, I have to start again and try and write more clearly." — Marcus Chown (04:27)

2. Bringing Science Alive Through People (05:23)

• Chown emphasizes interviewing living scientists to capture untold stories behind discoveries.
  • "You get off the phone after about two hours and you've got a notebook full of all these stories that nobody else knows." — Marcus Chown (05:41)

3. What Is a Black Hole & Why "From the Cold"? (06:14)

• Black holes: Regions where gravity is so intense nothing, not even light, escapes.
• Journey "from the cold": Once seen as absurdities, now pivotal in astrophysics—even Einstein doubted their existence.
  • "They have some mysterious role... they were the most ridiculous things. Even Einstein... didn't believe in them." — Marcus Chown (06:47)

4. Power of Naming — ‘Black Hole’ and Science Communication (07:44)

• Coining the phrase ‘Black Hole’ spurred research and public fascination.
• The label shaped imagination but led to common misconceptions — black holes can be some of the most luminous objects, not just "dark vacuums."
  • "Their most prominent features is often of stuff coming out, often in titanic jets..." — Marcus Chown (08:54)

5. Terminology & Misconceptions (09:23)

• Terms like "black hole" and "Big Bang" paint mental pictures that are misleading compared to the physics.
  • "In many ways, that is another term that stuck. That paints a picture which is completely at odds with the reality." — Marcus Chown (09:41)

6. Singularities: The Physicists’ Nightmare (10:29)

• Einstein’s general relativity predicted singularities (points of infinite density) inside black holes—leading even him to distrust the implications.
• The theory "contains the seeds of its own destruction."
  • "At these two points, the theory actually breaks down. So we know that the theory is not the final word..." — Marcus Chown (13:31)

7. Scientific Outsiders: Chandrasekhar and Schwarzschild (15:18)

• Review of Chandrasekhar’s derivation of the limit for black hole formation (Chandrasekhar Limit).
• Chandrasekhar and Schwarzschild were both outsiders, meeting resistance from the scientific establishment, especially Arthur Eddington.
  • "Eddington humiliated young Chandrasekhar... and it's really hard to understand why he did it." — Marcus Chown (19:01)

8. The Maverick: Roy Kerr and Rotating Black Holes (21:08)

• Roy Kerr solved Einstein’s equations for rotating black holes, showing every black hole is described by his equations—establishing their physical reality.
• Background: Kerr’s unorthodox rise from rubber band counter to Cambridge.
  • "He just thought differently to everyone else. He was a real maverick." — Marcus Chown (22:58)
• Ergosphere: Rotating black holes possess an "ergosphere," allowing energy extraction and explaining observed cosmic jets.
  • "If you were to cross... into the ergosphere... you would be swept around within this ergosphere." — Marcus Chown (25:33)

9. First Observational Evidence: Cygnus X-1 (28:15)

• The 1971 discovery of Cygnus X-1 by Paul Murdin and Louise Webster provided the first indirect proof that black holes exist.
  • "My God, these things actually exist." — Paul Murdin (quoted by Chown, 28:19)
• Chown stresses the essential, too-often-overlooked contribution of Louise Webster.
  • "Please remember the name of the co-discoverer of black holes, Louise Webster. Forgotten even in Australia." — Marcus Chown (48:41)

10. Theory vs. Observation in Science (31:16–36:58)

• Scientific discoveries about black holes often began with equations, then were confirmed by observation ("the mathematics precedes the data").
• Chown cites examples from planetary discovery to the electromagnetic spectrum.
  • "No one knows why the universe has a mathematical twin... Dirac said, God must be a mathematician." — Marcus Chown (34:27)

11. Detecting and "Hearing" Black Holes: Gravitational Waves (41:30)

• Gravitational waves, first detected in 2015, provided direct evidence of black holes merging.
• "We were actually hearing the universe for the first time." — Marcus Chown (42:29)
• These events are more frequent and produce larger black holes than anticipated.

12. Supermassive Black Holes and Galactic Structure (48:32)

• Supermassive black holes were identified as the engines powering quasars by Martin Schmidt; later shown by Hubble observations to exist in all galaxies.
• "Galaxies and supermassive black holes are two sides of the same coin. You cannot have one without the other." — (Cited by host from the book, 55:11)
• Relationship is based on energy released during their formation, shaping entire galaxies.

13. The Rules of Black Hole Growth (58:09)

• Supermassive black holes have a mass-to-galaxy ratio, currently ~0.1%.
  • "There is this ratio everywhere, and that's telling you that there is some intimate connection..." — Marcus Chown (58:27)
• JWST (James Webb Space Telescope) suggests these ratios may have evolved since the early universe.

14. Black Holes, the Early Universe, and the Unknowns (59:16)

• Massive, ancient black holes exist "too early" for conventional formation scenarios, possibly implying primordial origins ("seeded" at the Big Bang).

15. Black Holes and the Quest for a Unified Theory (61:28)

• Black holes bring together gravity (relativity), quantum theory, and thermodynamics—making them crucial in the search for a "Theory of Everything."
• "What you want in science is some domain where... they predict different things... that's a gold mine for physicists." — Marcus Chown (65:58)

16. Cosmic Perspective and Human Existence (72:45)

• Our Milky Way's relatively small supermassive black hole may have allowed multiple generations of stars, supporting habitable worlds and, by extension, us.
  • "Our existence is connected to the supermassive black hole at the centre of our galaxy." — Marcus Chown (75:36)

Notable Quotes & Memorable Moments

• On making science accessible:
  "I try and write the books that are accessible to my wife... If her eyes glaze over, I have to start again and try and write more clearly." (04:27)

• On the paradox of black holes:
  "They're neither black nor holes." (09:14)

• On unexpected discoveries:
  "That's why you do science. You do science to surprise yourself, really." (46:10)

• On science’s unfinished business:
  "Teachers really implied that science was sewn up and done, but it is so not sewn up. There are just so many really important questions that are occurring..." (71:44)

• On the connection between black holes and our existence:
  "It looks as if our existence is connected to the supermassive black hole at the centre of our galaxy." (75:36)

Timestamps for Key Segments

• Why write the book, and target audience – 03:23
• Chown’s interview-first method – 05:23
• What is a black hole? Why ‘from the cold’? – 06:14
• Importance of naming in science – 07:44
• Singularities and Einstein’s discomfort – 10:29
• Chandrasekhar and Eddington conflict – 19:01
• Roy Kerr and rotating black holes – 21:08
• Kerr’s childhood and maverick thinking – 22:58
• Ergosphere and energy extraction – 25:33
• Cygnus X-1 discovery and Louise Webster – 28:15, 48:41
• Theory vs. observation in science – 31:16–36:58
• Detecting black holes and gravitational waves – 41:30
• Supermassive black holes and galaxies – 48:32, 55:31
• Universal black hole-galaxy ratio – 58:09
• Black holes in the early universe – 59:16
• Theoretical black holes and the search for quantum gravity – 61:28
• Milky Way’s black hole and human existence – 72:45

Summary of Tone & Style

Chown and McNiff maintain a tone of wonder, curiosity, and plainspoken clarity throughout, frequently pausing for analogies and stories that make physics human. McNiff steers the conversation for both lay and expert listeners, ensuring key discoveries are contextualized through their personalities, struggles, social context, and enduring mysteries. Chown’s enthusiasm and humility are ever-present, blending fascination with accessible explanations.

Final Reflection

• The Big Takeaway: Black holes, once spurned as theoretical embarrassments, now sit at the heart of astrophysics and cosmology, linking the smallest and largest scales and perhaps connecting to the ultimate theory of reality.
• Essential message: The universe is both more knowable and more mysterious than ever. Through interviewing the pioneers themselves, Marcus Chown brings these cosmic questions down to earth—and shows how our very existence may hinge on the quirks and contours of a singular supermassive object at the center of our home galaxy.

Recommended for anyone seeking accessible cosmic wonder, the human stories of science, and a sense of just how much we still have to learn.