Why the Speed of Light cannot be Broken?

Why the Speed of Light cannot be Broken?

When we get to a certain base level of "why?" questions, the answer is always going to be "because." Our universe seems to be a game with certain rules (the Laws of Physics). Why those rules and not other rules?

Einstein  once called the speed of light “The Universe’s speed limit”. He claimed  that traveling faster than the speed of light would violate the  causality principle. For the layman, that means cause and effect. An  example of this would be a bullet hitting a target before the trigger  was even pulled.
Accelerating to light speed or exceeding it would also violate certain fundamental energy conditions. It could even allow for time travel.

Let's start with the simplest best possible scenario

The heavier something is, the harder it is to move. That's common sense, and we experience it every day. We expect to have a much easier time pushing a toy car than a real car or a marble than a cannon ball. The more something weighs, the more energy we need to push it.

(For accuracies sake, I should quit talking about weight and "heaviness" and talk, instead, about mass. The more mass something has, the more energy is required to move it. But since weight—which really only exists when mass meets gravity—is intuitive, I'll continue to evoke it. Think of it as a metaphor.)

So let's say we launch a really big space ship—say the size of the Starship Enterprise. We would expect it to require a lot of energy as propulsion. Worse, the faster things go, the more they weigh (the more mass they have), so if we keep trying to make the Enterprise move faster and faster, we'll need more and more energy to push it. At some speed, we'll need so much energy to push it, we'll use up all the energy in the Universe. Let's call that speed S.

Just as a recap, S is the speed the Enterprise can travel if we use all the energy in the Universe to push it.

What if we want it to move faster than S? 

Well, we're out of energy, so we have to make the ship lighter (we have to make it have less mass). If we jettison, say, all the crew members, the ship won't weigh as much. Which means we'll get more speed out of all the energy in the Universe. We'll be able to move the ship at speed S[1], which is some speed that's faster than S.

If we jettison all the chairs and tables, we'll be able to move the ship at S[2]. If we jettison all the shuttlecrafts, we'll be able to move at S[4]. Etc.

Let's keep breaking off parts of the Enterprise to get it to move faster and faster. Let's break off so much of it, that it only has one unit of weight (really mass) left. I'm not sure what the ship is now, but imagine it's a tiny little spec that is as light as an object can be. It moves at, let's say, S[5,000].

How could we make it move even faster than S[5,000]?

By making it weigh nothing at all! If the more something weighs, the more energy you need to push it, the way to get the biggest bang for your buck is to make the object you're pushing weigh nothing at all. Imagine how fast you could throw a baseball if it was totally weightless!

Alas, we can't make the Enterprise weigh nothing at all, but there is something that does weigh nothing: a photon. (Again, strictly speaking, a photon has no mass.) A photon is a particle of light. Since light particles weigh nothing, they can travel the fastest it's possible for anything to travel, which is, in the system I made up, maybe S[5,001].

As it happens, we know the real value of S[5,001]. It's around 180-thousand miles-per-second. That's how fast something can travel if it weighs nothing. And, if you think about what I wrote above, if it weighs nothing, it requires no energy to push it. As soon as you add a little weight to something, it requires energy to push, and the faster you push it, the more energy it requires. To push an object with weight (mass) at 180-thousand miles-per-second, you'd need more energy than exists in the Universe. So you're shit out of luck, Captain Kirk!

The lingering question here is why 180-thousand miles per second? What's magic about that? Why can't a photon travel faster than that? (Why can't light travel faster than the speed of light?)

As far as I know (again, Physicists, please correct me if I'm wrong), the answer to that is because. Because that's just the way our Universe is built. It's a physical law we acquired by being a product of the Big Bang. If there are other universes, perhaps the constant is faster (or slower) in some of them.

So why can’t anything go faster than the speed of light?

Before  we can dive into that, we have to know what the speed of light actually  is, what it means, and clear up some common misconceptions regarding  this “universal speed limit“.
The speed of light, (or the speed of a photon) in a near-perfect vacuum is exactly 186,282 miles per second.  We perceive photons (light) traveling at this speed because they are  massless, or have no ‘weight’ (but they do have kinetic energy, more on  that in a bit).
Every particle in our universe (including photons)  move or ‘swim’ through what scientists call “the Higgs field”. As a  result of this interaction, particles acquire their mass. Different  particles interact with the Higgs field with different strengths, which  is why some particles are heavier (have more mass) than others. Photons  move through, but do not interact at all with the Higgs field.

What does that mean?
Since  photons don’t interact with the Higgs field, it means they aren’t bound  by any speed limit. They’re free to move at the fastest possible speed –  their own “light” speed. Why isn’t the speed of light slower or faster  than 186,282 miles per second? It’s because that exact speed is a  fundamental constant of our universe.
Wondering why light doesn’t  travel at a different speed is like wondering why gravity isn’t reversed  or what it would be like if our universe only had 2 spatial dimensions  instead of 3 (4 if you include time). Those constants, along with the  speed of light, were set in place when our universe was created at the  moment of the big bang.

Universal Speed Limit

Particles  that have mass require energy to accelerate them. The closer to the  speed of light you get a particle, the more energy is required to go  faster. This is because the particles themselves get more massive in  proportion to the increased velocity. In short, the faster you go, the  heavier you get.
Thanks to this inconvenient truth, if you wanted  to accelerate a single electron to ‘light speed’, you would need an  infinite amount energy due to the electron becoming infinitely heavy.  There isn’t enough energy in the entire universe to propel just a single  electron to the speed of light.

From A Photon’s Perspective

One  of the methods Einstein used to help formulate his theory of special  relativity was to visualize what the universe would look like from the  perspective of a photon. Einstein saw that life as a photon would be  quite bizarre. For instance, if you were a photon, time would have no  meaning to you. Everything would appear to happen instantaneously.
Imagine  for a moment that you are a happy little photon created by a star in  another galaxy some 4 billion light years away. From my perspective here  on Earth, it took you exactly 4 billion years to travel from that star  till you reached my retina. From your perspective, one instant you were  created and then the next, you are bouncing off my eyeball. You  experienced no passage of time. Your birth and death happened  instantaneously.
This is because time slows for you as your get  closer to light speed, and at it, it completely stops. This is also  another reason why nothing can go faster than light. It would be like  slowing down a car to a stop, and then trying to go slower than  completely stopped.
One should think of the speed of light as  ‘infinite speed’. A common misconception is thinking the speed of light  is just like any other finite speed. The speed of light is only finite from the perspective of the outside observer; from the  perspective of a photon, it’s infinite. If you move at exactly the speed  of light you could go anywhere, no matter how far, in exactly zero  seconds.

So to sum up, nothing can travel faster than  light because the speed of light can be thought of as infinite speed.  To match or exceed it would be to go infinity miles per second/hour.