Stephen Hawking felt gravity’s pull. His quest to understand this feeble force spanned his career, and he was the first to realize that black holes actually disappear – slowly losing the mass of everything they swallow in a dull, evaporative glow called Hawking radiation.
But one of gravity’s deepest puzzles defied even his brilliant mind. How can we connect theories of gravity on the large scale to what happens on the very small? The Theory of Everything remains one of the great challenges to physicists.