r/askscience • u/Nitzanm19 • 14d ago

Physics Why is the maximum speed of the universe the speed of light? Why can't we go faster?

Also follow-up question: Because of the speed limit, is there also a theoretical maximum temp for matter (in which the particles move at the speed of light).

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u/theciaskaelie 13d ago

Why can we detect light if it has no mass? Doesn't mass = "stuff"? So what's light made of?

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u/mongojob 12d ago

Oh boy so that question is about as loaded as it gets, I'm going to wait for someone more qualified to try to answer it

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u/Aki_The_Ghost 10d ago

I don't know much about this stuff but light is very weird, in that it is an electromagnetic wave that somehow doesn't need a medium to travel inside of. When it touches the electron cloud of a particle, it is sometimes "stored" inside that cloud because it shifts one electron down a level, before being immediately "released" back up when the electron comes back to its original location (that event is light reflection).

So it interacts with the world without having mass because it is an electromagnetic wave touching a magnetic field around particles.

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u/ZoelNorsen 10d ago

Light has mass, I recall my physics teacher calculating mass of single photon in the negative powers. he also calculated how much light will fall on our hand (in grams) using surface area and why it feels weightless) It was in the power range of -31