Einstein and his peers were resistant to black holes
Einstein’s early skepticism toward black holes is used as a springboard to examine how physics handles singularities, event horizons, and the limits of general relativity. Commenters argue over whether black hole singularities are “real” or merely artifacts of incomplete theory, how much current observations (gravitational waves, EHT images) actually prove, and where quantum gravity is expected to change the picture. The conversation broadens into questions of what counts as rational scientific skepticism, how much trust to place in mathematical extrapolations without direct evidence, and whether our universe itself could be the interior of a black hole.
Einstein’s resistance and whether it was “irrational”
- Several argue his skepticism about black holes was reasonable given lack of observations and discomfort with infinities.
- Others note he at times responded with personal dismissals, which some see as irrational bias rather than pure reasoning.
- General theme: rejecting a radical prediction of one’s own theory purely on intuition is questioned, but understandable in historical context.
Singularities: real physics or model breakdown?
- Many commenters treat GR singularities as signs the theory breaks down, not literal infinite-density points.
- Expectation: a future quantum gravity theory will regularize singularities.
- Some point out that other continuous theories (e.g., fluid equations) also develop singularities that are artifacts.
- A minority defends physical singularities more literally, but this view is portrayed as rare or misinformed in serious GR.
Time, observers, and event horizons
- Strong disagreement over “time stopping” at the horizon.
- One side: to a distant observer infall appears to freeze; so maybe singularities never actually form from our frame.
- Counter: this is a coordinate illusion; locally, crossing the horizon is uneventful and collapse to a singularity (in classical GR) is unavoidable.
- Some emphasize the distinction between event horizons (global, need full spacetime) and apparent horizons (what we can infer now).
Interior structure and alternative pictures
- Ideas discussed: growing interior spacetime that avoids a final singularity; exotic “Bardeen-like” cores with non‑ordinary equations of state; ultra‑compact stars; or no true horizons at all.
- Multiple speculative cosmologies:
- Our universe as the interior of a black hole spawned in a larger universe.
- Black holes as entropy “recycling machines” or sources of new big bangs.
- Hierarchies of universes inside black holes debated as interesting but highly speculative.
Evidence for black holes and data skepticism
- Observational support cited: gravitational waves, dynamics at galactic centers, and EHT “shadow” measurements.
- Others remain cautious: EHT images involve complex reconstruction (including some ML); they prefer to treat black holes as still partly theoretical.
- Distinction stressed between “objects that look exactly like GR black holes from the outside” (strong evidence) vs certainty about interiors (unknown).
Rationality, bias, and language
- Debate over what counts as “rational” vs “irrational”:
- Some define irrational beliefs as those not originally arrived at via explicit reasoning.
- Others note this becomes circular and often just labels positions one disagrees with.