The upshot is that pairs of virtual phonons are appearing and disappearing all the time, and if one gets trapped inside a supersonic boundary, the other should be released into the wider world to make a noise.

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Her offensives were often scattershot, appearing at one rally and disappearing at the next.

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The problem is that for many large firms, systemic risk is a matter of exogenous events, sort of like comets which originate outside the normal operations of the solar system, suddenly appearing, flashing across the sky and then disappearing.

FORBES: 'Systemic Risk' Is Not Event Driven, It Is Character Driven

Most financial talk treats systemic risk as a matter of exogenous events, sort of like comets that originate outside the normal operations of the solar system, unpredictably appearing, flashing across the sky and then suddenly disappearing.

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