Q:

# What is the speed of light in miles per hour?

A:

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."

## Keep Learning

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Although 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.

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## Related Questions

• A:

Light travels at 186,282 miles per second, or approximately 670,616,629 miles per hour, in a vacuum. As of 2014, it is assumed that no object that has mass can travel at or above this speed.

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• A:

The speed of light in a vacuum is a universal constant, with a value of 299,792,458 meters per second. Nothing in the universe that has mass can, even theoretically, exceed this speed.

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• A:

Radio waves travel at a velocity that is equal to the speed of light traveling in a vacuum, which is 186,282 miles per second. Top speed is only possible in empty space; passing through transparent liquids and solids like crystals cause waves to bend, which slows down their speed.