If you’re travelling at a constant speed of half the speed of light, relative to a person on the ground, and you then throw a ball forward at a speed of just over half the speed of light relative to you, then at what speed does the observer on the ground see the ball travel at?
I know nothing can go faster than the speed of light, but since everything is relative, as far the you are concerned the ball isn’t travelling faster than the speed of light. We accelerate particles up to and over 99% the speed of light, while the earth is whizzing around the sun, so if the particles at the LHC were travelling in the same direction as the earth going around the sun, to a stationary observer on the sun wouldn’t they be travelling at the earth’s speed + their own? But this surely wouldn’t be possible if this led their speed to be greater than that of light?
