Is lightspeed really a limit? Solving super-luminal Special Relativity

I'd put my money on a hypothesis that says causality is enforced whether we can perceive it or not. Say we had such a computer with FTL circuitry. You attempt to instruct the computer to halt the current program when an answer is received, thus preventing the inputs being supplied that would produce the given output. Our current time-based perception says "paradox" whereas this proposed hypothesis would say "the computer simply will not halt the program," not because it's designed with safeguards, but because the laws of physics maintain causality.

The same argument could have been waged against the heliocentric model. Occam's razor is not a natural law after all.

Let's say you're moving nearly as fast as the speed of light. Are you flying side by side with light particles? No, because if they were, you would measure their speed as being close to zero relative to you. The theory says you will STILL measure the beams of light as flying away from you at the speed of light relative to you.

Imagine how the universe must conform to make that the case! The universe essentially makes your time tick slower in order for light to still travel that much faster relative to you.

This phenomenon has been confirmed (along with basically every other prediction that Einstein has made). There are some subatomic particles that we know has a half-life of X seconds. However, when they're traveling quickly, they actually end up living orders of magnitude longer because of time dilation.

In every day life, if you throw a ball at 70 mph on top of a car that's going 30 mph, the ball moves at 100 mph. You can't do the same math once you start reaching the speed of light.

It actually makes sense in that regard, because while accelerating, you will shrink along the acceleration vector.

Let's say you are 6 feet tall and fly Superman-style at 0.9c. You will then, from the outside, be 2.6 feet (or so). This means that if you from your timeframe accelerate by 1 km/s, to the outside you will accelerate by 0.4 km/s.

This acceleration in turn cause you to shrink even further, and as you approach the speed of light your external length will approach 0. So any further acceleration in your frame of reference, no matter how immense, would approach 0 from the outside.

[Edit: "the force required to double your speed" is pretty damn meaningless. What I"m looking for is something like "your mass effectively increases exponentially as your speed..." Sorry.]

[Edit v2: How about this: "For a given force, your acceleration decreases as if your mass were increasing exponentially as your speed approaches the speed of light."]

It should be obvious that if you travel fast you have energy. And the faster you go, the more energy, and the heavier you are the more energy.

Now comes the interesting part: That velocity energy you have increases your mass! As soon as you have this, some very interesting things happen.

As you get faster you get heavier, the heavier you are the more energy you need to go even faster. This positive feedback loop eventually results in you needing an infinite amount of energy to go any faster (since you are so heavy).

The point where you need infinite energy is at the speed of light.

Now comes the second interesting effect.

Suppose you accelerate to half the speed of light - you have a certain amount of energy - no problem.

Now someone else does that too - only in the opposite direction.

He too had no trouble accelerating, and needed only a finite amount of energy.

But what happens if the two of you are traveling toward each other? A problem - the total of your speed is greater than the speed of light! And even if it was slightly less, suddenly you got energy for free! (Because of the feedback loop going from 0 to 1/2 c takes MUCH MUCH less energy that from 1/2 c to 8/9 c. So where did that energy come from?)

That obviously is impossible - you can't get energy for free. Instead the very definition of speed is changed! You have no choice - you have to change it. The definition is changed in such a way that the energy remains constant. And if the definition of time and length has to change to make it work, so be it. Energy is more important.

Of course all this rests on a foundation: That the increase in speed results in an increase in mass. But this too is required. We already know that's it's possible to convert energy to mass. So we could use a trick - convert mass to energy, speed it up, then convert it back to mass and suddenly we have mass moving very fast without putting in energy. Nope, can't do that. What actually happens is that energy has mass too, and this doesn't work. (If energy didn't have mass you could do other tricks, like send the energy up to space, convert it back to mass and let it fall under gravity.)

Hopefully this should show you why relativity is required if you have conservation of energy.

Onlookers at your destination would not see you until you arrived but ones from your departure would see you leave and you would be invisible to another craft going at the same speed as you.

All you've done is explained a word by simply repeating it.

The reddit comment doesn't explain anything either - as the very first comment under it says.

If you want an actual accessible explanation see my comment: http://news.ycombinator.com/item?id=4637451