[Animats]

A fundamental question, of course, is whether FTL is possible. Special relativity says it isn't, and worse, that it would violate causality. We're probably fundamentally limited to having very slow conversations with any civilization that's within tens of light years. If any. We might find out about some that are further away, but there's not going to be interaction.

[gmueckl]

Well, this is our world view now. But we cannot predict future progress. Just as we laugh at the horribly wrong cosmological models of our ancestors from the middle ages now, our ancestors might do that with ours in a few centuries.

The interesting thing about both theories of relativity is that they only add one or two rather small ideas to existing theories each (electrodynamics and Newtonian mwchanics) and derive sweeping fundamental facts about our spacetime from that. Most of the building blocks were already there, but were not recognized for what they really are. The theories have held up very well to all direct tests we could come up with so far. This makes chances that there are loopholes or omissions left right there rather slim (based on our current knowledge, of course). There are oddities like solutions to the field equations that allow time travel. But as far as I know, these are mathematical oddities and unphysical solutions.

I have never understood how the destruction of quantum entanglement can avoid violating causality. Our professor confused us to no end at this point in the lecture and I have never tried to follow up on my own.

[xelxebar]

Entangle the spins of two electrons; put one on Pluto and keep the other on Earth. How do you propose to send your FTL single bit?

The usual idea is that since "wave function collapse is instantaneous" we can measure the spin on Earth, collapse the superposition and then Pluto can "notice the collapse".

However, there's no way to notice that entagled particles have decohered without looking at both of them side by side. Or said another way, the entire planet Earth could be entagled with some giant blob of matter in an alien lab in Andromeda, but we have no way of discovering this without comparing Earth matter with the alien lab matter.

I've got my unreasonable hopes pinned on some incarnation of the Alcubierre Drive. Just gotta find that negative energy density first :)

[Jyaif]

If humans start to be able to live millennia, speed of light becomes less of an issue.