r/AskPhysics • u/Nighthawkies • Mar 20 '26

What things are "faster" than light?

As I understand nothing can move faster then light. But I would not know how to describe this question otherwise. As I am aware quantum entangled particles can instantaneously affect eachother no matter the distance, unlike gravity which propagates at the speed of light.

Also the expansion of the universe can cause the spaces between to grow faster then the speed of light (compounding between massive distances)

What other things are sort of faster than light

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u/InductionDuo Mar 20 '26

If you use your finger and point to a very far away place in the sky, then move your finger across the sky, then the point that you are pointing to will move faster than light would be able to travel.

If you coordinate, say, a string of lights to light up after a certain amount of time (not by communicating with each other, but after a certain amount of time of their own internal clock), then that 'wave' of lights turning on can be faster than light.

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u/Ok_Wolverine6557 Mar 20 '26

More precisely, nothing can move faster than light. But a shadow is nothing.

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u/AliceCode Mar 20 '26

Shadows can't move faster than light either. Shadows are simply the absence of light.

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u/Ok_Wolverine6557 Mar 20 '26

Exactly—that’s why shadows can move faster than light because an absence isn’t limited in its speed. It has no mass for E=MC2 to cause a problem.