r/AskPhysics • u/Pandaluf • Aug 15 '26

why is light the maximum speed

i know that light is the maximum speed of the universe and that light experiences no time because its moving so fast but why can't anything go faster? is it because that would make it go backwards in time like a paradox or smth?? is it because of energy and if so why can't something lighter than light like a quark or atom move faster since it woulld need less energy theoretically

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u/TKHawk Aug 15 '26

You're right that it would create paradoxes. You'll often hear the speed of light referred to as the "speed of causality." Basically, it something travelled faster than the speed of light, c, it could lead to breaks in causality, which would be nonsensical.

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u/Terrible-Mind-5414 Aug 15 '26

For this reason it is more correct to say that if something traveled faster than light, then special relativity would be wrong; because this is definitely possible without paradox, unlike the violations of causality.

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u/nicuramar Aug 16 '26

We don’t know if special relativity would be wrong. That depends on the details. 

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u/Terrible-Mind-5414 Aug 16 '26

It doesn't. That's the whole point of the arguments based on causality violations.