Re: Why we can\'t reach the speed of light?
Well here it is the way I see it:
The thing to remember is that any object moving through a medium faster than the speed at which the medium carries waves will generate waves on each side, automatically, just from the motion itself. This is why a tractor with an absolutely silent engine moving faster than approximately 741.45 mph in air under standard atmospheric pressure, a temperature of 30 degrees Celsius, and a typical carbon dioxide concentration will produce a shock wave and the resulting sonic boom.
At first one might think nothing can move faster than the speed of light. However, light in glass has a phase velocity less than the speed of light in a vacuum, and it is possible to shoot a charged particle of very high energy through a block of glass such that the particle velocity is close to the speed of light in a vacuum, while the speed of light in the glass may be only 2/3 the speed of light in the vacuum. A particle moving faster than the speed of light in the medium will produce a conical wave of light with its apex at the source, like the wave wake from a boat (which is from the same effect, as a matter of fact) or the tractor in the above mentioned scenario. By measuring the cone angle, we can determine the speed of the particle. This is used technically to determine the speeds of particles (or tractors) as one of the methods of determining their energy in high-energy research. The direction of the light is all that needs to be measured.
Rogue
