This topic also came up a few weeks ago. I speculate there is no upper bound. A similar example using "Hawking": https://news.ycombinator.com/item?id=30626497#3

This topic also came up a few weeks ago. I speculate there is no upper bound. A similar example using "Hawking": https://news.ycombinator.com/item?id=30626497#30653029 https://news.ycombinator.com/item?id=30626497#30653029