so this image gave me time to think about teleportation machines.
I do think that travelling arbitrarily close to the speed of light (i.e. practically instant) might be doable, and probably actually is, but it would be so expensive that nobody would use it anyways.
i mean, you can just build a rocket and accelerate it arbitrarily close to the speed of light, using enough fuel. but the cost of doing so is prohibitively expensive, so there's no practical way to actually ever do that in practice.
slow travel is just much more economical, that's why teleportation is out of the question. but that's economical reasons, not a fundamentally physical one.
this comic argues that through teleportation machines, travel would become instant and cheap. and i think it's the opposite: the faster, the more expensive.
teleportation machines probably work by accelerating every part of you to the speed of light and slowing them down again on the other side. so it really is like a rocket acceleration.
and no, they wouldn't kill you any more than stepping on an airplane does.
there's also this existential comics about it that argues:
but that's already the case on an airplane. if you drink a cup of water on the airplane, the atoms inside your body get swapped out for new ones; that literally happens all the time. so it partially kills you? but nobody thinks that way. (ship of theseus)
I never understood this take, or most takes implying that the "take 'em apart and put 'em together" form of teleportation wouldn't be the holy grail of science.
Being able to teleport something is cool and all, but the thing that people should care about much much more is what that actually means: you are disassembling and reassembling a person or object at the atomic level.
This means, you are able to take an arbitrary collection of atoms, and build it into an arbitrary formation.
That's not a teleporter, that's a matter printer. Any and all economic implications of teleportation become mute, as the entire concept of an economy becomes irrelevant with the ability to print anything out of literally dirt and rubbish.
Even the concept of human life becomes practically worthless, since if you can put together a human, what's to stop you from putting together 2? Or 20? Or put together the latest backup of someone who died?
If anyone ever manages to invent this kind of teleportation, it would matter for about 3 seconds before being eclipsed by whatever consequences this has for humanity as a whole - good and bad.