Tags: time and space

tech contradiction

(no subject)

Is NC = P under time travel? It would seem so, as communications are instantaneous. If that's correct, then the inequality "at least one of NC, P, NP, PSPACE is not equal to the others" does not hold if you have access to a CTC (not Vasai -- closed timelike curve :) ).

Of course, then you get something which destroys realism in science fiction:

- Faster than light travel plus relativity implies time travel (or CTCs).
- Time travel implies easy calculation of PSPACE-complete problems.
- Easy calculation of PSPAC-complete problems implies extreme artificial intelligence.


That is, unless you like your Singularity brief and powerful.

(Wrt my universe, computers that powerful would only get in the way. Thus.. STL.)

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On that note, here's something I wrote when trying to come up with realistic (STL) starship warfare strategies. I don't know if I reached that goal, but it could be interesting to read in any case.
The big problem with STL starship warfare is that there probably isn't going to be any - when it takes your fleet a year to meet up with the enemy, that kinda hampers things. (Unless you have "hyperspace nodes" or "jump gates" that only exist at certain points and thus need to be defended. But then you aren't strictly STL anymore, unless you create a loophole to the effect that what we thought was vacuum has a slow c, but true vacuum (or whatnot) has very high values for c.)
GVA

(no subject)

The dinosaurs, they were right. Time is a spiral, neither forging straight nor locked in endless repetition. [1]

This is good because you can anticipate; it is bad when it assumes the strength of fate. More balance; neither excessive order nor chaos overreaching helps.




[1] And it makes sense; a clockwork fueled by free choice and randomness, neither determined nor arbitrary. Still, seeing the outcome, you want to change it, but if you have not the direction, it cannot be.

I digress further now.. It is interesting how giving some the power to change gives others less choice, hardening them into more gears in the clock; their actions dissolved from their consequences, seeming chaotic, leads to even more "order", but the order of stone, of immobile static rigidity.
Dwight

Quite spontaneous

If you can send a message faster than light (no matter how it works), then you have a time machine, something which would mess up causality.

(That is, unless there's a common Universal Time, which relativity says doesn't exist)

All FTL comms as well as wormholes and warp drives count, but reactionless slower than light ones don't.

There's also a trick - go fast enough and time goes slower for you than for others, so you can get to another solar system before you die. The problem is everybody you know where you started will, or at least be much more older than you.

--

Something to ponder: drop enough matter into a black hole and friction heats that matter up, forming a disk that releases lots of energy before it's swallowed. But everything you drop into the black hole will be spewed out by it later as Hawking radiation, so where did the energy come from?