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It was an old idea of Stephen Hawking’s: Unseen “primordial” black holes might be the hidden dark matter. A new series of studies has shown how the theory can work.
Renormalization has become perhaps the single most important advance in theoretical physics in 50 years.
Physicists have identified an algebraic structure underlying the messy mathematics of particle collisions. Some hope it will lead to a more elegant theory of the natural world.