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Originally Posted by Hemi-Cuda
that same thing was said about even getting humans into space in the first place, we couldn't survive the radiation or lack of gravity. humans are insignificant in the grand scheme of things and we haven't even explored a fraction of the universe, so i find it quite ignorant to claim that we know the absolute speed limit of that universe. just because we haven't seen it broken doesn't mean it can't be
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You are misunderstanding that particles already travelling at the speed of light do exist. The thing is that you cannot accelerate something like a spaceship from sub-light to the speed of light. You could get to 99.9% but anymore is impossible.
Because of E=MC^2, as your space ships' velocity increases so does its mass. As its mass increases so does the amount of energy needed to accelerate it further. As its speed approaches the speed of light the amount of energy required to accelerate further approaches infinity, which is of course an impossible situation. Infinite energy is more energy than in the damn universe. Therefore you can never accelerate that ship to the speed of light. It's not arrogant, it's the law of spacial relativity regarding the speed of light in a vacuum. It has nothing to do with human survivability which is another issue entirely.
When people said in one era that things like men in space were impossible, it was likely not the scientific majority or simply the voice of skeptics with small imaginations (whereas the entire scientific community agrees on special relativity). It's not arrogance to think that faster than light travel is impossible, in fact, it takes a great deal of imagination to think up solutions to go around this problem.
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Originally Posted by worth
Well, technically speaking some things do travel faster than light.
The universe is 14 billion years old.
But the universe is also 126 billion light years across.
Therefore, if we started from a single point in space, aka the big bang, and 14 billion years later we are 126 billion light years across, how did it get to be that big?
The universe is ever expanding. It's like a loaf of rising bread, and the galaxies in it are the rasins in the bread. As the universe expands, the galaxies are pulled apart from each other.
I was actually quite shocked when I found out the universe was over 100 billion light years across. Boggled my mind because I knew the universe was only 14 billion years old.
Now that example is a little different than matter. Physics as we know it is based on the principal of the speed of light being a constant in a vaccuum, and matter can only infinitley approach the speed. I believe experiments have been done to try to go over the speed of light, but in doing so, we would probably have to rewrite some textbooks.
Time dialation and other forces when traveling near the speed of light are enormous. I couldn't imagine the difficulties if your traveling faster than the speed of light. It doesn't seem realistic to me either.
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You are oversimplying the idea of the universe's size being limited by it's age.
For the issue of the universe being approx 14 billion years old yet approx 158 billion (yes, 158 is now the closest estimate) lightyears across...this is another matter that has more to do with general relativity and is more complicated to explain. Physicists say that what is happening is that the masses that comprise galaxies are not moving apart at superluminal speeds, but rather the space between them is expanding at faster than light speed. This is an issue of cosmic expansion (see Hubble Radius) and not accelerating something to superluminal speeds. Your raisin bread analogy is actually totally accurate, you are just misunderstanding how it's intended to be used. It's hard to imagine but the raisins in the loaf are not moving very much at all but the actual loaf is expanding. The raisins are staying in the same place (not moving faster than light) in the loaf but the loaf itself is growing and expanding between and around the raisins.
This goes back to why any theories about effective space travel for humans cannot take place within the confines of special relativity and so most likely needs take advantage of theorized phenonmenon like wormholes, subspace, etc.