The Reflection Property of a Hyperbola

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This animation demonstrates the reflection property of hyperbolae. (See notes below.)


When a photon is emitted from one focus of a hyperbola and strikes a branch of that hyperbola, it is reflected so that it behaves as though it had come from the other focus. Here, a red pulse is emitted from the left focus and strikes the right branch of the hyperbola. A green pulse is emitted from the right focus, timed so that the two pulses hit the vertex of the right branch simultaneously. Note the striking effect: The wavefronts appear to exchange places. (11/16/07)