Can one hear the shape of a black hole singularity?

4:30PM, 21 Oct 2026

Sean Hartnoll shows how the ringing of black holes reveals chaotic dynamics near their singularities and hints at hidden mathematical order.

Black holes hide spacetime singularities, where tidal forces become infinite and time comes to an end. The approach to a singularity is thought to be chaotic, yet its average behaviour may follow a deep number-theoretic symmetry known as modularity.

Outside a black hole, the picture is very different. Disturbances rapidly die away, leaving a characteristic ‘ringdown’ as the black hole settles back into equilibrium. Gravitational-wave observations in 2015 detected a low-frequency quasinormal mode associated with this ringing. For two decades, physicists have known that much higher-frequency modes encode information about spacetime near the singularity, accessible through a mathematical technique called analytic continuation.

In this colloquium, Prof. Sean Hartnoll explains recent work connecting these two seemingly opposed regimes. He shows how the chaotic dynamics near a black hole’s singularity leave a trace in its quasinormal modes—and how listening to that ringing can reveal the mathematics of the black hole’s interior.

Event information

This event takes place at 4:30pm on Wednesday 21 October in the Faraday seminar room of the London Institute for Mathematical Sciences, on the second floor of the Royal Institution. LIMS colloquia are sponsored by Cognia.

Can one hear the shape of a black hole singularity?
Can one hear the shape of a black hole singularity?
Can one hear the shape of a black hole singularity?
Can one hear the shape of a black hole singularity?
LCP
Can one hear the shape of a black hole singularity?
Can one hear the shape of a black hole singularity?
Can one hear the shape of a black hole singularity?
Can one hear the shape of a black hole singularity?
Can one hear the shape of a black hole singularity?
Can one hear the shape of a black hole singularity?
Can one hear the shape of a black hole singularity?
Can one hear the shape of a black hole singularity?
Can one hear the shape of a black hole singularity?
Can one hear the shape of a black hole singularity?
Can one hear the shape of a black hole singularity?
Can one hear the shape of a black hole singularity?

Speakers

Sean Hartnoll

Sean Hartnoll is the 1967 Professor of Mathematical Physics at Cambridge. He studies gravity, high-energy physics and quantum matter, and their fundamental connections across modern physics. He received the Presidential Early Career Award in 2013 and the New Horizons Prize in 2015.