Word: evens
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Dates: during 1990-1999
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...short enough durations, space-time loses its apparently smooth, continuous structure, devolving into what Princeton physicist John Wheeler calls "quantum foam." The orderly flow of events may really be as much an illusion as the flickering frames of a movie. And according to independent physicist Barbour's new book, even the apparent sequence of the flickers is illusory...
Then came trains and factories, and with them the need to coordinate the schedules of hundreds and even thousands of people. It was the railroad companies that invented time zones, in 1883. Because of the earth's rotation, the sun was highest at different times in New York City and, say, Washington, which lay a bit farther west. The 11-min. difference in local noon could lead to disaster at intersections...
...such a timepiece would be virtually useless today: computers, communications satellites, global-positioning receivers and telephone-switching systems need a precision beyond anything conceivable even 50 years ago. Time technology long since abandoned mechanical devices and even the hum of quartz crystals. For true precision--accuracy to a billionth of a second--you need to travel, virtually at least, to a place like the perfectly circular, well-guarded park that sits in northwest Washington. There, on the grounds of the U.S. Naval Observatory, a nondescript concrete building houses the nerve center of the U.S. Directorate of Time...
...even the most accurate clock in the world can't answer the question of what all these atoms are actually measuring. What is time anyway? According to Isaac Newton, both space and time were fixed attributes of the universe, a God-given stage on which events unfolded. But Albert Einstein torpedoed that idea with his theories of special and general relativity: the only thing that's fixed in the cosmos, he showed, is the speed of light...
This elasticizing of space-time means, for example, that observers might disagree over which of two events happened first--and both could be right. Even more bizarrely, physicists including Stephen Hawking have seriously discussed the possibility that relativity might make it feasible (though not with any technology we know of today) to send objects backward in time...