The speed of matter

23 Jul 2012, 10:03AM

Two facts that we are fairly certain of in physics:

1) Light only ever travels at one speed - c
2) Matter can travel at anything from 0 up to c

It seems weird to me that first these two behave differently (why can't light go at slower speeds?) and second why there is a limit on the speed of matter. I can understand if say it is travelling through a medium (e.g. the Luminiferous Aether) and there is drag (think terminal velocity) but I think we have ruled this out with the Michelson-Morley experiment. So if there is no aether, what is stopping matter from going faster (as you approach the speed of light) while you keep applying a force to it? There must be some force that is in play here that we don't know about.

They say that the force is converted into mass as you approach the speed of light. You can take this as a fundamental but it still doesn't make sense to me.

So I made up an answer that does make sense (to me). And it comes from (and supports) another facet of physics - time dilation. This is another area that doesn't make sense. How can time slow down? Is it possible that we actually age slower? I've talked about time in prior posts and it being an illusion (and, I believe, not coupled to space).

So lets consider a single hydrogen atom (such as may exist in our bodies), an electron orbiting a proton. Now lets accelerate this to the speed of light. If we assume that the speed of light is an absolute limit (I know we're trying to understand this better but bear with me for now) then the electron can no longer orbit the proton or else at some point it would be going faster than the proton (as the proton is now travelling at the speed of light). So we therefore see that the proton and electron are both travelling next to each other at the speed of light, as if time had stopped for them. We can understand that if the hydrogen atom is travelling at a little less than the speed of the light then the electron can orbit the proton but it must do so at a much slower speed than the speed of light (at least in one part of its orbit).

Lets now consider temperature (such as between the atoms in our body). Temperature is simply average kinetic energy or more simply the amount of jiggling between atoms. Cold atoms jiggle little and hot ones jiggle a lot. Now if we accelerate our body to the speed of light we see that temperature must also cease to exist. All jiggling between atoms must stop, as if there was back and forwards motion then the atoms would be travelling faster than the speed of light (and we know through experiment that this is a physical limit). Extending this we could say that all motion between atoms must cease for the same reason. Blood cells must stop flowing around the body, electrons in the brain can no longer travel down neurons, the heart can no longer pump and muscles can no longer move. For all intensive purposes time has stopped, physical movements of atoms has ceased. And extrapolating back, something travelling at a little less than the speed of light must have all its atoms moving slower than they would normally (e.g. time is moving but slower).

Amazing really, especially when you realise that this effects everything in the same way so that your movement AND your thinking has slowed, so you DON'T NOTICE THAT TIME HAS SLOWED DOWN.

Ok, so this (maybe) explains time dilation. What does this have to do with the speed of matter? Why does matter have this limit? It stumped me for a while. I think the reason I ask this question as it seems a little arbitrary and I totally subscribe to the line of thought that [the underlying] physics should be simple and beautiful. So I came to the following conclusion...

That there is only one speed for everything, light and matter. Everything travels at the speed of light. There are no exceptions, anywhere or anyhow.

What this means is that matter must be made up of smaller [things] travelling at the speed of light. The simplest analogy I can think of is this. We know that two photons of the right energy can form an electron. Lets then imagine the electron as those two photons orbiting in a tight circle. The circle gives the impression of a point particle to us that is stationary in our frame of reference. We can then move this "system" to any speed inbetween that of stationary and the speed of light, but not larger than. This would explain why matter has this speed limit and is much simpler than other explanations. It does still leave the question - how does energy turn into matter (and vice versa).

The speed of light then is simply one "arbitrary" constant. Nothing more. Just like the value of Pi, it just has the value it has. That is the speed of matter, energy, anything and everything. That is the only speed allowed.