There is nothing in the entire universe faster than the speed of light.

Not only is light the fastest thing, but nothing can ever be faster than light.

For the longest time humans didn't even know that light had a speed,

and once they figured out that light wasn't instantaneous,

it took several centuries to determine what that speed was.

Learn more about the speed of light and its implications for physics and engineering,

on this episode of Everything Everywhere Daily. The speed of light in a vacuum is exactly 299, 792,458 meters per second.

This is a universal speed limit. Nothing can go faster. It is literally impossible.

Before I get into the implications of this fact and what it means, I should start with how we even know that light has a speed.

Light is so incredibly fast that from a human perspective it seems instantaneous.

For the longest time nobody was sure if light was instantaneous or just really fast. It was a subject of debate for philosophy. was light did a finite speed. Aristotle, on the other hand, said,

quote, light is due to the presence of something,

but it is not a movement.

Hence, he didn't think it had a speed,

but was rather instantaneous.

The Aristotelian view held sway for centuries.

Much of this had to do with the fact that most people thought that light emanated from the eye.

According to Heron of Alexandria, light had to be instantaneous because when you open your eyes, the stars could be seen immediately.

The Aristotelian view was challenged by the Islamic scientist, Hassan Ibn Al-Hatham in the 11th century. He wrote a

treaties called the Book of Optics, which argued for the intro mission theory of

light, which said that light entered the eye from the outside, and this led him to conclude that light must have a finite speed.

These debates continued for centuries with no real resolution.

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