What are black holes? And how are they formed?
Black holes are probably the most fascinating (theoretical) objects in astronomy. Such objects, which scientists believe must exist, would account for the spin-rate of our galaxy, which cannot be explained by the combined mass of the visible stars. But exactly what are black holes?
A paper, "Philosophical Transactions of the Royal Society in London," written as early as 1783 by John Michell, a Cambridge don, pointed out how a star which...