Hacker News new | past | comments | ask | show | jobs | submit login

There is a neat physical argument that was made back when quasars and the like were just being discovered. Basically if the flash of brightness only lasts an hour, then you can argue convincingly that the source of the flash must be less than a light-hour across. The faster the flash, the smaller the bound on the size of the phenomena. This is what lead people to realize that quasars are wildly energetic but necessarily very small



Applications are open for YC Winter 2020

Guidelines | FAQ | Support | API | Security | Lists | Bookmarklet | Legal | Apply to YC | Contact

Search: