Francis raised her hand, "The crab nebula, which was seen in 1054 AD, is recognized today as the brightest supernova remnant in the sky. Approximately 940 years before the Crab attained its current appearance, a massive star exploded with the power of 400 billion Suns. It left behind a rapidly rotating neutron star and a cloud of ejected gases flying outwards at speeds of 1000 kilometers per second (or 2.2 million miles per hour)."
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