The speed of light is a fundamental constant of the universe, meaning that no matter where an observer is or how fast they're traveling, the speed of light remains the same. Although it's called the speed of light, the measurement is actually the speed of any particle that has no mass when traveling through a vacuum. As a constant, the speed of light is an important part of a lot of scientific work, especially for physicists. It's no surprise, then, that scientists spent centuries calculating exactly how fast light travels.


1. What is the Speed of Light?

At it's most simple, the speed of light is the speed at which light travels through space. The exact speed of light is 299,792.458 kilometers per second (kps) or 186282.397 miles per second (mps). This is often rounded up to 300,000 kps or 186,000 miles per second. The speed of light is commonly denoted by a c in equations.

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