i always curious why we say that when there are right in front of our eyes evidence to the contrary - galaxies moving away with speeds higher than the light speed. FTL is impossible only in SR - ie. in the static continuous space-time - which is only approximation (and not really true) of the real space-time.
Space itself is expanding - so galaxies really far away are being pushed away FTL but they're not actually 'moving' FTL. They couldn't travel that fast towards us, or indeed towards anything.
are being pushed away FTL but they're not actually 'moving' FTL. They couldn't travel that fast towards us, or indeed towards anything.
it is kind like saying that because all stones fall down, one can't fly or jump. Like stone falling down, space expansion (cooling down) is an entropy increasing process. What we know is that any entropy increasing process can be reversed by applying energy (which gets obtained by even more increasing of entropy somewhere else).
Yes, if you permit (human controlled/manipulated) space warping. It is currently unknown if this can actually be engineered due to the requirements for exotic matter. Sure, a primordial wormhole could just "exist" and we could use it, but the more exciting question is whether or not we can warp space without astronomical, uneconomical, and unknown, exotic masses.
Comments
i always curious why we say that when there are right in front of our eyes evidence to the contrary - galaxies moving away with speeds higher than the light speed. FTL is impossible only in SR - ie. in the static continuous space-time - which is only approximation (and not really true) of the real space-time.
They aren't moving FTL locally.
Space itself is expanding - so galaxies really far away are being pushed away FTL but they're not actually 'moving' FTL. They couldn't travel that fast towards us, or indeed towards anything.
it is kind like saying that because all stones fall down, one can't fly or jump. Like stone falling down, space expansion (cooling down) is an entropy increasing process. What we know is that any entropy increasing process can be reversed by applying energy (which gets obtained by even more increasing of entropy somewhere else).
Yes, if you permit (human controlled/manipulated) space warping. It is currently unknown if this can actually be engineered due to the requirements for exotic matter. Sure, a primordial wormhole could just "exist" and we could use it, but the more exciting question is whether or not we can warp space without astronomical, uneconomical, and unknown, exotic masses.