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Why you age slower on a plane?
According to the theory of relativity, the faster you travel, the slower time will pass for you. While the effect may be small, it is still significant. For instance, if you were to embark on a transatlantic flight from London to New York, the time displayed on your watch would be slightly behind that of a watch left on the ground by a ten-millionth of a second. This seemingly minuscule difference in timekeeping actually translates to you aging a fraction more slowly than if you had chosen to stay at home.
The Hafele-Keating experiment, conducted in 1971 by physicists Joseph C. Hafele and Richard E. Keating, stands as a seminal test of Einstein's theories of relativity. At the heart of the experiment were highly precise cesium atomic clocks, which served as the tools to investigate the effects of time dilation predicted by special and general relativity.
Cesium atomic clocks operate based on the vibrations of cesium atoms, which resonate at a specific frequency. The stability of these vibrations allows for incredibly accurate timekeeping. In the context of the experiment, the researchers strategically placed atomic clocks on commercial airliners that circumnavigated the globe in opposing directions.
Einstein's theory of special relativity, formulated in 1905, predicts that time is not absolute but rather relative to the observer's motion. Specifically, time dilation occurs when an object is in motion relative to an observer at rest. Clocks in motion appear to run more slowly, an effect proportional to the object's velocity. This concept was a fundamental departure from classical Newtonian physics, challenging the notion of a universal and absolute time.
The Hafele-Keating experiment tested these principles by sending atomic clocks on flights. Clocks traveling eastward, in the direction of the Earth's rotation, were expected to experience less elapsed time than stationary clocks due to their high speed. Conversely, clocks flying westward against the Earth's rotation were anticipated to register more elapsed time.
The results of the experiment were in line with the predictions of special relativity. Clocks that flew eastward recorded less time compared to their stationary counterparts, while clocks flying westward recorded more time. This experimental validation added significant weight to the revolutionary ideas introduced by Einstein in the early 20th century and demonstrated the practical implications of relativity on our understanding of time. The success of the Hafele-Keating experiment underscored the profound impact of Einstein's theories on our comprehension of space, time, and the nature of the universe.