- all those photons are blue-shifted and becomes hard gamma rays.
- once you get close enough from c, all the stars in the universe appear to be either right in front of you, or right behind you, which means you get hit not only by gamma photons coming from the galaxy you're aiming at, but gamma photons coming from half the universe!
once you get close enough from c, all the stars in the universe appear to be either right in front of you, or right behind you
That's not really right. There is a distortion where things appear more in front of you than they are at the time you see them, but that's only because they were at that angle, but by the time the light gets to you they're not where they appear.
Also there's nothing that would shift light to appear behind you other than your movement away from objects that you have passed.
I think this is why the Alcubierre drive will become critical even at well below light speed. Assuming I understand the physics correctly, the bubble of space around the ship is not moving (very fast) relative to the ship and so moving at fractional c will see an increase in flux but not the blue shift. You’re still hitting every spec of dust in your path, but not turn the entire cone of the universe in front of you into gamma rays.
At some point the warp drive might be cheaper than the shielding.
If an alcubierre drive can be created,even inside the bubble of normal space time you would probably die. This is because of the Unrue radiation that is created by compressing the space time in front of you. Also, it seems that even with the best theoretical approach you still need the mass equivalent of Jupiter in exotic matter to make it work for a small ship :/ Spacetime is extremely resistant to compression/expansion.
Think of it like walking in a rainstorm. Walk at a slow pace and most of the rain hits your head, but if you're moving very fast all of the rain will seem to be coming from the front because you are running into it instead of it running into you.
If you travel very close to c (relative to everything else) then due to length contraction everything else in the universe is 0 metres away. Likewise time appears stopped on everything else moving close to c relative to you, due to time dilation. (Is this right? I've never thought of it this way before).
Blue shift (aka increased apparent frequency) is caused by the velocity between you and the source, not the velocity of the source. That is how the speed of light works in General Relativity. If you move toward a photon is doesn’t get faster, it gets higher frequency. If that’s in the visible range it shifts toward the blue end of the spectrum.
If you move fast enough, all of the ultraviolet light coming from behind you becomes visible light. A little faster and all of the ultraviolet light in front of you becomes X-rays. And all of the hard x-rays become gamma rays.
Even if the photon is coming from the side, just slightly ahead of you, you are ramming into it at near lightspeed. You can't add up speeds in newtonian way so energy goes (for you) into blueshift.
- all those photons are blue-shifted and becomes hard gamma rays.
- once you get close enough from c, all the stars in the universe appear to be either right in front of you, or right behind you, which means you get hit not only by gamma photons coming from the galaxy you're aiming at, but gamma photons coming from half the universe!