nothing with mass can reach the speed of light

Why can't you ever see a car zoom by at the speed of light?

Imagine you're standing on a sidewalk, watching cars pass by. The faster they go, the harder they seem to move. But there's a limit to how fast they can go, even if you wish they could.

As cars get closer to the speed of light, they need more energy to go any faster. It's like trying to push a heavy ball uphill – the harder you push, the heavier it feels. This idea is explained by the Lorentz factor γ, which shows how things like time and space change when you're moving really fast.

Example

If a car normally takes 2 seconds to pass, as it speeds up close to light speed, it would seem to take 10 seconds to pass, just from your perspective.

Remember this

The Lorentz factor γ shows that as you approach the speed of light, it requires infinite energy to go any faster, which is why nothing with mass can reach light speed.

Text adapted from Wikipedia, licensed under CC BY-SA 4.0.

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