(why I love speculative philosophy)

[gusl]

quote of the day:

"If the speed of light provides an upper bound on the expansion speed then the amount of resources under human control will grow only polynomially (~ t3). Population, on the other hand, can easily grow exponentially (~ et). "

Comments

[gustavolacerda.livejournal.com]

I had thought of wormholes as an objection, but not relativity.

but from the point of view of a 3rd party observer, they are still going slower than light, right?

It's so hard to reason relativistically... it's like the very foundations of my intuitive physics fall apart, and I feel like I can't prove anything anymore. Do you have any good guidelines for reasoning about these kinds of questions? Do you know of logic of relativity?

[spoonless.livejournal.com]

I personally don't believe wormholes will ever work in the way sci-fi shows present them, ie I don't think there's any way we'll be able to make large ones and use them for transport. However, the possibility is not entirely ruled out scientifically so I suppose it's a valid objection.

but from the point of view of a 3rd party observer, they are still going slower than light, right?

Yes, that's correct. As you say, it's complicated and somewhat counter-intuitive to think about. But the way I see it, the scenario is just as good as exponential expansion in time... because we could still let the natural birth rate happen with no population control and never run out of resources. (Aside from eventually running out if they are only finite... or, the expansion of the universe might become a problem before that too, I'm not exactly sure how that factors in.)

The reason I think it's just as good is... we could keep putting new towns on ships and sending them out at extremely high velocities radially away from the population centers. Their aging process gets slowed down, which is just the same as saying they have more time to live their lives and travel further out than they would normally have. So it's kind of like they're getting extra life-time for free... but their birth-rate from the perspective of the original population center is slowed down... so from that perspective it's like a natural population control!

One issue with this is, the fast-travelling ships would have to stop now and then to pick up resources when they found new resources. But assuming a lot of advanced technology that we might have by that time, they could either just stop briefly... or maybe even scoop them up as they're travelling and keep going.

I agree with your original point though... that it's kind of absurd to speculate on this, since it's so far in the future and who knows what will change in our technology, birth-rate, lifespans, and understanding of science by then.

It's so hard to reason relativistically... it's like the very foundations of my intuitive physics fall apart, and I feel like I can't prove anything anymore. Do you have any good guidelines for reasoning about these kinds of questions? Do you know of logic of relativity?

If you just hear quotes and results from it without knowing why, it's extremely counter-intuitive. But it's very logical and makes a lot of sense if you learn the whole framework of it. I'm not sure I can boil it down to a few "guidelines" for reasoning. I think the biggest one is to remember that you always have to consider things from a particular perspective (reference frame) otherwise you'll get horribly confused. Almost every error in thinking about relativity that I've seen comes in some way from forgetting that and trying to compare things half in one frame and half in another. Oh, and another big one is to remember that simultaneity of events depends on the frame... ie, if two events happen in one order for one person they might not necessarily happen in the same order for another.