Answer: GRAVITATIONAL COLLAPSE

The star apparently has to go on radiating and radiating and contracting and contracting until, I suppose, it gets down to a few kilometers radius when gravity becomes strong enough to hold the radiation and the star can at last find peace. -- Eddington, 1935

I felt driven to the conclusion that this was almost a reductio ad absurdum of the relativistic degneeracy formula. Various accidents may intervene to save the star, but I want more protection than that. I think there should be a law of Nature to prevent the star from behaving in this absurd way.

Eddington's supreme authority in those years effectively delayed the development of fruitful ideas along these lines for some thirty years. -- Chandrasekhar, 1980

Black Holes form on 2 scales: