Bug Splat Galaxies with Mordecai-Mark Mac Low

June 30, 2026

AI Summary

5 min read

In 1940, an astronomer used lamps and photodetectors as an analog computer to simulate colliding galaxies. The lamps stood in for gravity because light intensity drops off with distance the same way gravity does. That crude setup produced the first "bug splat" — the tidal tails and distorted shapes that would later be recognized as the signature of galaxies crashing into each other. Mordecai-Mark Mac Low, a computational astrophysicist at the American Museum of Natural History and one of the earliest hires into Neil deGrasse Tyson's department, has spent decades refining those simulations. His work has turned what were once mysterious "peculiar galaxies" into a predictable sequence of cosmic collisions, and it has recently led to a startling prediction: supermassive black holes may be surrounded by millions of planets.

From Bug Splats to Elliptical Galaxies

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What you'll learn

1 (01:28) **Introduction: The Violent Universe** - Neil deGrasse Tyson introduces the topic of planetary formation and his guest, Mordecai-Mark Mac Low, a computational astrophysicist.
2 (05:14) **Galactic "Bug Splats" and Collisions** - Mac Low explains how computer simulations solved the mystery of "peculiar galaxies" that look like bug splats.
3 (08:04) **What Happens When Galaxies Collide?** - A breakdown of the mechanics of galactic collisions.
4 (10:05) **Active Galactic Nuclei (AGNs) and Quasars** - Mac Low explains the physics behind the brightest objects in the universe.
5 (21:00) **Planet Formation Around Black Holes** - A new research frontier: forming planets in the accretion disks of supermassive black holes.
6 (27:36) **The Sticky Problem of Planet Formation** - Mac Low discusses the challenge of getting dust grains to stick together without breaking apart.
7 (33:30) **Turbulence, Magnetic Fields, and Star Formation** - Answering a detailed listener question about the regulation of star formation.

+ Full timestamped outline available in the app

Show Notes

What type of planets orbit black holes? Neil deGrasse Tyson and comic co-host Negin Farsad sit down with Mordecai-Mark Mac Low to crack open the mysteries of galaxy collisions, dark matter, and the massive planetary systems around black holes.

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