#16 Janna Levin - Black Holes, Singularities & Wormholes

Episode Overview

• The episode features a deep dive with physicist Janna Levin into the black hole information paradox, exploring its conflict with quantum mechanics and the modern resolution suggesting spacetime is an emergent property.
• The conversation clarifies fundamental concepts about black holes, including the nature of singularities as inescapable points in time and the distinction between point and ring singularities.
• The discussion explores other cosmological theories, such as primordial black holes as a potential candidate for dark matter and the unlikelihood of astrophysical white holes.
• Janna Levin shares the mission behind her non-profit cultural center, Pioneer Works, which aims to merge the worlds of art and science and make them accessible to the public.

Key Concepts

• Black Hole Information Paradox: The conflict between general relativity (which suggests information is lost in a black hole) and quantum mechanics (which requires information to be conserved).
• Hawking Radiation: The process where virtual particle pairs are separated by a black hole's event horizon, causing the black hole to emit radiation and eventually evaporate.
• Monogamy of Entanglement: The quantum principle that a particle can only be fully entangled with one other particle, which is violated in the original formulation of the information paradox.
• ER=EPR Conjecture: The modern theory that equates wormholes (Einstein-Rosen bridges) with quantum entanglement, suggesting spacetime is "stitched together" by these quantum connections.
• Singularities: The infinitely dense center of a black hole, which is not a physical location to be avoided but an inevitable moment in the future for an observer inside the event horizon.
• Primordial Black Holes (PBHs): Theoretical black holes formed in the early universe that are considered candidates for dark matter, behaving more like fundamental particles than collapsed stars.
• Emergent Phenomena: The idea that different physical laws and properties (like spacetime itself) can arise at macroscopic scales from more fundamental quantum interactions.

Quotes

• At 24:47 - "Now I'm trying to non-monogamously entangle the thing that escaped with its pair that fell in, and then with something that fell in a billion years ago. And that is not allowed by quantum mechanics." - Janna Levin precisely identifying the violation of the monogamy of entanglement, which is the core of the paradox.
• At 35:45 - "The very spacetime is kind of stitched together by these quantum wormholes... these entangled wormholes are like threads in a fabric... you actually coherently weave them into the fabric of spacetime." - Janna Levin using a powerful analogy to describe the advanced idea that spacetime emerges from a network of quantum entanglements.
• At 49:38 - "To the person falling in... they measure that as a point in time." - Janna Levin clarifying a common misconception about singularities, explaining that once you cross an event horizon, the singularity is no longer a physical location but an unavoidable moment in your future.
• At 56:34 - "They are much more like microscopic, fundamental particles than they are like macroscopic stars." - Janna Levin describing primordial black holes, suggesting they are not formed from collapsed matter but are instead elementary entities.
• At 70:54 - "We're building the world we want to live in because it doesn't exist yet." - Janna Levin articulating the guiding principle behind Pioneer Works, her cultural center dedicated to fostering a space where art and science can collide.

Takeaways

• Modern physics suggests spacetime is not fundamental but is an emergent property woven from a network of quantum entanglements, a concept that helps resolve the black hole information paradox.
• Once an observer crosses a black hole's event horizon, the singularity ceases to be a location in space and becomes an inescapable moment in the future.
• Primordial black holes are a compelling candidate for dark matter because they would behave like fundamental particles, defined only by mass, spin, and charge, rather than the complex matter that forms stars.