Science: Fastest Thing

The great Galileo Galilei (1564-1642) tried to measure the velocity of light by means of lantern signals between mountain tops. Naturally he failed. Light travels about 186,270 miles (more than seven times the circumference of Earth) in one second. In modern physics, light is regarded as the fastest thing in the universe, and its velocity in empty space as a fundamental constant of nature.

First good figure for light's speed was obtained in 1676 by a Danish astronomer, Ole Roemer, who measured the variations in eclipse times of Jupiter's satellites according to Earth's distance...

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