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J. Perelman
"Entertaining physics". Book 2.
Chapter 10. Sound. Wave motion

THE PHENOMENON OF DOPPLER

The phenomenon we have just described, was openly physicist Doppler and will forever remain associated with the name of this scientist. It is observed not only for sound, but for light phenomena, because light is a wave. Frequency waves (perceived in the case of sound waves as a rising tone) is perceived by the eye as the color changes.

Rule Doppler gives astronomers a wonderful opportunity not only to find out whether approaching star to us or deleted, but even allows you to measure the speed of this move.

Help the astronomer produces a lateral displacement of the dark lines, Proreznaya spectrum band. Careful study, in which direction and how much has shifted dark lines in the spectrum of the heavenly bodies, has allowed astronomers to make a number of amazing discoveries. Thus, due to the Doppler phenomenon we now know that the bright star Sirius every second away from us 75 km. This star is from us at such an incredibly great distance that removing even billions of kilometers does not change significantly its apparent brightness. We probably never would have learned about the movement of this light, if we were not helped by the Doppler phenomenon.

With startling clarity affects this example, the fact that physics is the science truly comprehensive. Installing the law for sound waves, reaching a length of several meters, she applies it to a vanishingly small wavelength of light, the length of only a few desyatitysyachnyj tenths of a millimeter, and uses this knowledge to measure rapid movement of the giant suns in the incredible vistas of the universe.

Entertaining physics J. Perelman

 




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