Black Hole basics
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•Escape velocity from a surface at radius R:
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•Imagine a collapsing object like a star.  As R shrinks (but M is fixed), Vescape gets larger and larger
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•At some point VEscape= c  (speed of light)
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–Happens at the “Schwarzschild radius”:
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–Not even light can escape from within this radius, which gives us a “black” hole
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