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Unformatted text preview: Frequency ↔ Small Wavelength
Low Frequency ↔ Long Wavelength
Vacuum speed is constant. Historical Background
• Before Galileo’s time (around 1600), many people believe that light was infinitely fast. It’s so fast that it seemed like it took no time to get from one place to another. Galileo and an assistant went to the Italian countryside, a mile apart, and tried to measure the speed of light by timing it. All they could determine was that light is much faster than sound.
• Later that century (around 1667) a Danish astronomer named Ole Roemer made the first accurate measurement of the speed of light. He had been observing one of Jupiter’s moons, Io (which Galileo had discovered). As Io circled Jupiter, it would be eclipsed by Jupiter periodically. That is, Jupiter would block Io’s view from Earth at regular intervals. Each time Io orbited Jupiter, an eclipse would occur. The time between the eclipses was the period of Io’s orbit. Roemer noticed that the eclipses sometimes took a little longer,...
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- Fall '11