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Practice Listening: Fill in the Blanks (Type In)
ID: #4017
Short
Cold
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Now researchers have stopped light cold and then brought it back to life or light in an different place. The Harvard researchers sent a light pulse into a sodium cloud cooled to about 460 degrees below zero. That’s the theoretical point where stops all movement. The light pulse was compressed by a factor of about 50 million at the temperature, and it actually changed state sort of like frozen water. But it also split into two forms of matter. One stayed in the sodium, while the other crawled along at just 200 meters per hour. That second form called a matter wave contains the exact information of the light wave. And when researchers sent it into a second sodium cloud a fraction of a millimeter away, the wave was back into light. And since fiber optic use light, that means that someday we may be able to stop them, store them and turn them back on, just like a light switch.
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