What If Dark Matter Is Just Black Holes?
Summary
This episode explores the hypothesis that dark matter could consist of primordial black holes, systematically ruling out most mass ranges using astrophysical evidence. The hosts examine constraints from supernova rates, Hawking radiation, and microlensing surveys to demonstrate that black holes likely cannot account for the majority of dark matter. While a few narrow mass windows remain untested, the episode concludes that dark matter is probably a new form of physics, ending with a brief mention of hypothetical Planck relics.
Topics discussed
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Introduction: The Dark Matter Mystery
Hypothesis: Dark Matter as Black Holes
Requirements for Black Hole Dark Matter
Methodology: Ruling Out Mass Ranges
Ruling Out Stellar Black Holes
Primordial Black Holes: Formation
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Early Universe Density Fluctuations
Ruling Out Supermassive and Tiny Holes
Constraints from White Dwarfs and Neutron Stars
Microlensing and MACHOs
Microlensing Survey Results
Intermediate Mass Black Holes
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Constraints from Dwarf Galaxies and Binaries
Conclusion: Black Holes Unlikely
Planck Relics and Naked Singularities
Outro and Sponsors: Bose and Notre Dame
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