# Claude Fable 5.2 completes a 23-year-old black-hole calculation

> Original title: Claude Fable 5.2 cracked a black-hole calculation that physicists had left unfinished for 23 years.

- Source: Rohan Paul
- Published: 2026-11-09T22:59:11.000Z
- Bad Influence: https://badinfluence.news/items/jb6cchz97se8cjcbrpmyels6z
- Original: https://x.com/rohanpaul_ai/status/2119927810517324048

## Summary

Anthropic's Claude Fable 5.2 completed a calculation on black hole formation in small universes that physicists had left unfinished since 2003. According to the post, Claude did most of the work largely on its own and found that black holes also form abruptly in those universes. A physicist has reportedly checked the work.

## Why it matters

The post explains the 1983 Hawking-Page result and the 2003 unfinished calculation, giving context for why the new result matters to black-hole physics.

## Post

Claude Fable 5.2 cracked a black-hole calculation that physicists had left unfinished for 23 years.

A physicist has already checked the work, i.e. this is new knowledge in fundamental physics that came largely from an AI.

In 1983, Stephen Hawking and Don Page showed that when a certain kind of universe heats up, a black hole forms suddenly, like water hitting boiling point, but their method only worked for large universes.

In 2003, physicists laid out the calculation needed for tiny universes, but it was so long and tedious that nobody finished it, until Claude did it largely on its own and found that black holes form suddenly there too.

![](https://badinfluence.news/api/img-proxy?u=https%3A%2F%2Fpbs.twimg.com%2Fmedia%2FHWt-nIjbcAEuJUt.jpg&mode=thumb&exp=1794528000&sig=36ba52ae25dd777b)

## Quoted post @claudeai

> Fable 5.2 solved two open problems in theoretical physics related to black holes.
> 
> In the first, Fable 5.2 completed a laborious calculation that had gone unsolved for 23 years.

https://x.com/claudeai/status/2119899484373369278