Black Holes
Black Holes
One-line summary: Regions where gravity bends spacetime so severely that nothing escapes; observable only by their shadow and the brilliantly hot gas trapped around them.
The insight
A black hole forms when a dying star's core collapses into a "bottomless pit of gravity." Per michelle-thaller, we don't know if there's an interior — "all the equations blow up; time and space don't exist in there." What we observe is indirect: the shadow of the event horizon (imaged by the event-horizon-telescope), stars whipping around the galactic-center black hole, and the extremely bright accretion disk and jets. Every major galaxy hosts a central supermassive black hole; the Milky Way's is ~4 million solar masses, with the largest known reaching tens of billions.
The chain
How the giant central black holes formed is an open frontier: the early dense universe may have collapsed huge gas cores directly into black holes (not stars), which then accreted and merged into supermassive holes. Canonical: direct-collapse-to-supermassive-black-holes.
Evidence
- joe-rogan in 2026-05-28-youtube-powerfuljre-joe-rogan-experience-2506-michelle-thaller: "In the center of every galaxy, there's a supermassive black hole that's one half of one percent of the mass of the entire galaxy."
- michelle-thaller in 2026-05-28-youtube-powerfuljre-joe-rogan-experience-2506-michelle-thaller: "It seems to be correlated... the bigger the galaxy, the bigger the black hole." (refining Rogan's relayed figure)
- michelle-thaller in 2026-05-28-youtube-powerfuljre-joe-rogan-experience-2506-michelle-thaller: "They managed to make a telescope that's actually as big as the Earth, and they were able to take a picture of the dark parts of a black hole." (the event-horizon-telescope)
- The Milky Way's black hole (~4M solar masses) is located via stars like S2 orbiting it at up to 20–50 million mph; jets from accretion disks can extend >100,000 light-years. Nothing escapes the hole itself — the brightness is from gas trapped around it.
Contradictions / tensions
"White holes" (a hypothetical other end of a black hole) had a following in the 1960s–70s but have "fallen out of favor" — the super-bright objects once attributed to them are now understood as hot accretion-disk gas. Whether a new universe forms inside a black hole (or whether our universe is itself inside one) is flagged explicitly as conjecture, not observation.
Open questions
- Is there an interior to a black hole, and what governs it? (current physics gives up — see neutron-stars for the parallel)
- what-is-time near an event horizon.