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Proving our universe is one among many would be a fourth Copernican revolution

nautil.us

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Re: Proving our universe is one among many would be a fourth Copernican revolution

#41

Post by jobigoud »

tabtab wrote: post #13
analog31 wrote: post #12

Earlier quoted context omitted.

Ah, but if someone on a distant planet were to record their perspective, e.g., data about their visible universe, and transmit it to us, it would be consistent with our perspective by the time it reaches us. For instance, stars that they can see but we can't, would become visible to us as their message reached us.

They couldn't transmit such a message; the part beyond "the wall" is moving away faster than light: the data would never reach us. From our perspective, their earlier era is "frozen" in time: red-shifted to zero. We cannot receive any "new" signal from them. Therefore, the seeming "faster than light" violation is not really the case. Relativity "fixes" it by mucking around with time. From a practical perspective, the…

> the part beyond "the wall" is moving away faster than light: the data would never reach us

To nitpick, the wall itself is moving away at about one light-year per year. The photons that are not moving from our perspective because they are receding away from us at the speed of light will soon find themselves in a space where they are again moving towards us.

"we routinely observe galaxies that have, and always have had, superluminal recession velocities" -- Davis & Lineweaver.

Re: Proving our universe is one among many would be a fourth Copernican revolution

#42

Post by nikofeyn »

lisper wrote: post #7

> We can only see a finite volume—a finite number of galaxies. That’s essentially because there’s a horizon, a shell around us, delineating the greatest distance from which light can reach us. But that shell has no more physical significance than the circle that delineates your horizon if you’re in the middle of the ocean. No, that's not true. You can rise above the surface of the ocean. Barring some major unforeseen…

i don't understand what you are "no, not true"-ing. it's just analogy. you pointed out a flaw if one happens to take the analogy too far, but i don't see the point when the original analogy was clear enough what they are getting at.

Re: Proving our universe is one among many would be a fourth Copernican revolution

#43

Post by albertgoeswoof »

prmph wrote: post #28
_emacsomancer_ wrote: post #25

Earlier quoted context omitted.

If other universe contain all logical possibilities, then yes. David Lewis talks about this and points out the moral issue is that even if you choose to do good things in this universe, in some universe your alternate is a psychopathic torturer, so decisions to do good don't actually lessen universal suffering, if calculated across all alternate universes. I think his conclusion was that it's still desirable to local…

But, apart from the moral absurdities, there are logical inconsistencies. In a certain universe, there will exist a God capable of influencing all other universes, and thus constraining the set of possibilities, no?

And yet in another universe there’s a god that controls the other god.

Re: Proving our universe is one among many would be a fourth Copernican revolution

#44

Post by marmaduke »

yters wrote: post #40

Proving our multiverse is one among many will be the fifth Copernican revolution. Proving this sequence of Copernican revolutions is one among many will be the aleph one Copernican revolution.

Did you apply the Y Combinator there?

Re: Proving our universe is one among many would be a fourth Copernican revolution

#45

Post by lisper »

nikofeyn wrote: post #42
lisper wrote: post #7

> We can only see a finite volume—a finite number of galaxies. That’s essentially because there’s a horizon, a shell around us, delineating the greatest distance from which light can reach us. But that shell has no more physical significance than the circle that delineates your horizon if you’re in the middle of the ocean. No, that's not true. You can rise above the surface of the ocean. Barring some major unforeseen…

i don't understand what you are "no, not true"-ing. it's just analogy. you pointed out a flaw if one happens to take the analogy too far, but i don't see the point when the original analogy was clear enough what they are getting at.

I am disputing the claim that "that shell has no more physical significance than the circle that delineates your horizon if you’re in the middle of the ocean".

Re: Proving our universe is one among many would be a fourth Copernican revolution

#46

Post by tvmalsv »

dsp1234 wrote: post #39
tvmalsv wrote: post #36

Earlier quoted context omitted.

I would say "yes" to that. But fortunately, with the load being so widely distributed, the load on our "local" quantum computers would effectively be zero (ie. x/inf). Unless, of course, our universe is the oddball and most others are running at full capacity. That's a depressing possibility.

The load could be zero, it could be infinite, or anywhere in between. Infinite universes sending infinite work is inf/inf. It's not possible to know if that's going to tend towards something like 0 or something like positive infinity without having some way to measure. But it's an error to just assume it's zero.

I completely agree. I was thinking it highly unlikely that other universes would be operating at full efficiency, so the average would more on the zero side. But, yeah, that's not how infinities work I suppose :) Still, I'm enjoying thinking about it.

Re: Proving our universe is one among many would be a fourth Copernican revolution

#47

Post by davesque »

yters wrote: post #40

Proving our multiverse is one among many will be the fifth Copernican revolution. Proving this sequence of Copernican revolutions is one among many will be the aleph one Copernican revolution.

I think it would be the aleph naught revolution, no? :)

Re: Proving our universe is one among many would be a fourth Copernican revolution

#48

Post by tvmalsv »

btilly wrote: post #18
lisper wrote: post #7

> We can only see a finite volume—a finite number of galaxies. That’s essentially because there’s a horizon, a shell around us, delineating the greatest distance from which light can reach us. But that shell has no more physical significance than the circle that delineates your horizon if you’re in the middle of the ocean. No, that's not true. You can rise above the surface of the ocean. Barring some major unforeseen…

According to current cosmological thought, the laws of physics at that shell are very close to if not identical to the laws of physics here. And yet, that shell is retreating from us faster than the speed of light. The shell is ever expanding, but we shall never see what that current shell will look like when it is 10 billion years. How can that be, you ask? It is quite simple. The speed of light is a limit on how fa…

It's also worth noting that, in a sense, the shell is actually shrinking. Every moment, more of our observable universe disappears "beyond the veil", so-to-speak, as the universe on our side of the edge transitions from near-light-speed to beyond light-speed outside the shell. (I know that's a sloppy way to use the speed of light, but it works for me.)

Re: Proving our universe is one among many would be a fourth Copernican revolution

#49

Post by wallace_f »

snackman7 wrote: post #22
lisper wrote: post #9

Earlier quoted context omitted.

Well, yeah, but our perspective is the only one that can possibly matter for us. There may be unicorns and leprechauns out beyond our light cone for all we know, but what possible reason would there be to care?

Is the only reason to investigate the universe to look for ways to exploit it?

The argument is it's beyond our observable universe. It's not possible to be investigated as we can receive no information.

Re: Proving our universe is one among many would be a fourth Copernican revolution

#50

Post by tdfx »

prmph wrote: post #28
_emacsomancer_ wrote: post #25

Earlier quoted context omitted.

If other universe contain all logical possibilities, then yes. David Lewis talks about this and points out the moral issue is that even if you choose to do good things in this universe, in some universe your alternate is a psychopathic torturer, so decisions to do good don't actually lessen universal suffering, if calculated across all alternate universes. I think his conclusion was that it's still desirable to local…

But, apart from the moral absurdities, there are logical inconsistencies. In a certain universe, there will exist a God capable of influencing all other universes, and thus constraining the set of possibilities, no?

The gods are sandboxed, so unless they've discovered an escalation vulnerability in the multiverse substrate, they can execute any permutation of possible behavior but never affect the lower layer. If that happens, it's back to "turtles all the way down" as we then try to figure out what's running the multiverse VM.
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