The speed of light in a vacuum is measured at 186,282 miles per second, which is 670,616,629 miles per hour. The speed of light is denoted mathematically by the symbol "c."
Know MoreAlthough early scientists thought that light traveled at an instantaneous speed, later experimentation concluded that there was a finite speed. Two French physicists in the mid-1800s, working simultaneously on different experiments, arrived independently at results that were within 1,000 miles per second of an accurate answer. It wasn't until 1879 when Prussian-born Albert Michelson, working in the United States, used a high-quality system of light beams, lenses and mirrors to arrive at the result of 186,355 miles per second, the most accurate measurement for the next 40 years.
Learn more about PhysicsThe speed of light when traveling through air is roughly 670,398,880 miles per hour. This number can be determined by dividing the speed of light in a vacuum by the index of refraction of air.
Full Answer >The speed of light in mph (miles per hour) is 6.702 x 108 mph or more precisely 670,616,629 mph. In metric units, the speed of light in a vacuum is 2.998 x 108 m/sec.
Full Answer >In a vacuum, the speed of light is 186,282 miles per second. This is equal to 299,792 kilometers per second or about 670,616,629 miles per hour.
Full Answer >When light travels in a vacuum, its speed is 186,282 miles per second. The fastest aircraft, which is the Boeing-43 scramjet, has a speed of 7,546 miles per hour. If these two speeds are compared, the jet's speed is approximately 0.0004 percent that of light.
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