British astrophysicist Stephen Hawking has done a lot of thinking about the nature of the universe. While the renowned scientist has lived most of his 71 years with a paralyzing disease, his pioneering efforts to unlock the secrets of the cosmos have revolutionized astrophysics and captured the imagination of millions.
Astrophysicist Stephen Hawking

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These two globular star clusters, located beyond our Milky Way galaxy, harbor hundreds of thousands of stars. Deep within the clusters’ dense cores, stars whirl rapidly around intermediate-sized black holes. (NASA/Hubble)

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In this illustration of a black hole and its surrounding disk, gas spiraling down into the black hole piles up just outside it, creating a luminous halo. (NASA)

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The smallest known black hole – part of a binary star system named XTE J1650-500 – is about 3.8 times more massive than our Sun. (NASA/CXC/A. Hobar)

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This cosmic beach ball displays a full-sky map of the microwave radiation left over from the Big Bang event that created the universe 13.7 billion years ago. (NASA)