eli5 how do we know nothing is faster than light?
In: 452
When we were in school we were taught that mass was the amount of matter an object had, which is pretty much true at non-relativistic speeds, but is a total lie in relativity! Turns out the best way to look at mass is simply as a resistance to accelerate when acted on by a force, and once you approach the speed of light, the resistance to accelerate when acted upon by a force (mass) approaches infinity. Why this happens, beats me, relatively is where I drew the line.
While others have given you exhaustive answers, there’s still a caveat. [We actually can’t measure one-way speed of light](https://en.wikipedia.org/wiki/One-way_speed_of_light?wprov=sfti1). While you would never move faster than light in the same direction, you might be faster than light moving in another direction in respect to your movement.
Because as far as we can see, and calculate, the fabric of space-time is curved in such a way that the fastest possible speed between any two points in space-time is *c*, that is, 3×10^(8) m/s or so.
(Sort of like the shortest possible distance between any two points in space. But… with the added time-dimension.)
If the fabric of space-time were shaped differently, then maybe that speed would be different. But then if that were the case, a *ton* of experiments and observations we have done over the past 150 years would have all come out differently.
So let’s say I’m in a spaceship going 99.9999999999999% light speed. I have a laser pointer in my hand. I stand at the back of my spaceship and shine my laser to the front….how fast is the light from the laser going? I’m obviously missing something here but I’m curious
From what i understand the dumbed down version, when any “thing” with mass moves, it becomes heavier. So anything with mass will just get insanely heavy the closer it gets to high speeds. Essentially it gets so heavy as it approaches the speed of light, it can never truly reach the speed of light. Light photons on the other hand dont have any mass as they are photons.
The speed of light seems to the same, no matter your point of view or how fast you move.
If you assume that is the case, then it turns out that anything going slower than light (which, by the way, is every bit of matter we’ve ever seen), then it can’t end up going faster than light.
Think about it, no matter how fast you go, light goes ‘the speed of light’ faster than you, so you can never catch up, no matter how fast you move!
–
The maths appears symettrical, so, hypothetically, if something was going faster than the speed of light, then maybe it would be forced to always go faster than light, and be unable to slow down.
So, even if there are a lot of ‘superliminal’ objects, we might struggle to detect them due to their strange behaviour. But, I think more likely is that they simply don’t exist.
Very simple explanation from Veritasium. Awesome videos overall.
So, excuse my naïveté, if we DID find some speed faster than the speed of light would it cause a massive rewrite of physics? Im just saying there was Galileo or that our founding fathers didn’t know dinosaurs existed. I’m wondering how much we know that could not be absolute. I’ve always found this fascinating and totally over my head.
Latest Answers