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Never ending outer space.... 
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#1
Feb1112, 09:00 PM

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Outer space is never ending and infinite in size. At least that's what I assume. The confluence of events that it took to create earth the way that it is and the galaxy that it is in was like a 1 in a centillion to the centillionth power event. Being that outer space is infinite and never ending, that would mean that earths, EXACTLY like the one that we are living on, have been created an infinite amount of times. Because there are an infinite amount of centillion to the centillionth powers in infinity. Is this logic correct??



#2
Feb1112, 09:13 PM

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Welcome to PF,
If you just picked an arbitrarily large number out of the air in order to make the point that this probability is vanishingly small, then I wholeheartedly agree. Especially when you factor in the part about the planet being "exactly" the same, right down to the development of life and history of events. 


#3
Feb1112, 09:33 PM

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Now that I think about it some more, given that we don't even know if the problem is welldefined (i.e. whether it is possible to define/compute the probability of said event), I am not sure if I can assert anything with confidence, nor am I sure whether both an infinite amount of time and an infinite amount of space are required, or whether simply having an infinite amount of space is sufficient.
Assuming that we can define the probability of what you describe, and assuming that it is nonzero, then that would lead me to be believe that we could compute the expected number of such identical planets that would occur per Hubble time (age of universe, essentially) and per Hubble volume (i.e. volume of the *observable universe*  the part of it that we've had enough time to be able to see so far). Since this number is (speaking in the hypothetical) nonzero, and if there are infinitelymany Hubble volumes in the universe, then naively I WOULD expect there to be an infinite number of extant duplicate Earths. So I may have spoken too hastily before. I don't know the answer, or whether there is even a welldefined answer. 


#4
Feb1112, 09:37 PM

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Never ending outer space....
I'm hypothesizing a "flat" or "open" geometry.
Yes, I am guessing. Um, isn't that what most of this is????? LOL!....the number "1 in a centillion to the centillionth power" is just meant to show that Earths creation and its development and sustainability of life as we know it happened against EXTREMELY long odds (to say the least). The frequency of how often planetary systems like Earth are created is mute when you are considering infinity (or the abuse there of). I am not purely discussing OUR universe here, and I am aware that OUR universe has a finite age. I'm am discussing the vast expanse, known in laymen terms, as outer space. Which, as I mentioned in the 1st sentence, is infinite for the purposes of this discussion :) 


#5
Feb1112, 09:42 PM

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#6
Feb1112, 09:42 PM

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I don't think "time" is relevant for the purposes of this discussion. Given an infinite amount of space and the smallest odds of something happening simultaneously in that infinite amount of space, time is irrelevant, in more ways than one.



#7
Feb1112, 09:52 PM

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this is going to sound stupid........and make fun of it if you so desire......but if I give you every possible ticket for the lottery today, you're going to win, no matter what the odds are, they become irrelevant...........if I give you every possible combination and ticket again the next day, you're going to win again. And this is a stupid small example of how I think of infinite space. It's never ending (for the purposes of this discussion). So, (for the purposes of this discussion) this Earth has happened an infinite amount of times and at the same "now" that this Earth is currently existing, albeit, infinities away from here :)



#8
Feb1112, 10:02 PM

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and I am aware that "infinities" is not a viable concept....lol.......it was just a bit of hyperbole on my part :) :)



#9
Feb1112, 10:06 PM

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I don't think time is totally irrelevant to the discussion. You can't form an Earth when it's so early that the universe is so hot and dense that stable atoms don't even exist. You can't even form an Earth after the universe has cooled somewhat, but just consists of a mostly smooth/homogeneous distribution of neutral hydrogen gas with only a few small density fluctuations that haven't grown yet under their own gravity to produce structures. You still can't even form an Earth after the first luminous, selfgravitating objects (e.g. stars) have formed, but not enough time has passed for them to produce heavy elements (that planets are made out of) and to die and spread those elements throughout space. My point? There is some earliest time before which a planet cannot exist, let alone one that is exactly like the one we're sitting on now. So I imagine that the probability is a function of time, and if we were somehow having this conversation at some other epoch, the answer would be different. You may have an infinite amount of space, but it matters when. 


#10
Feb1112, 10:19 PM

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#11
Feb1112, 10:27 PM

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I once attended a lecture by Dr. Ken Krane, he used a very similar argument about an infinite universe to show that a traveler could not tell if he has arrived at the identical world which must exist in a infinite universe or returned home in a closed universe. The question being, of course, is the universe open or closed.



#12
Feb1212, 12:27 AM

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Integral  good to know that smart people who've actually thought about this somewhat confirm our naive view 


#13
Feb1212, 12:34 AM

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Although that's interesting, becuase I guess Crane's scenario for the infinite universe involves happening upon an exact copy of our entire local universe including clusters, the local group, the milky way, the solar system etc. How else would one be fooled?



#14
Feb1212, 12:51 AM

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Infinites invite paradoxes. Let's start with what we do know. We can say with some confidence the universe has a finite age. The spatial part is unclear. It might be finite and unbounded, or, it might be infinite  with nearly all of it forever beyond our observational reach. I have issues with that. How can a spatially infinite universe be temporally finite? And if it is spatially infinite, what observable effects might that have on our comfortable little patch?



#15
Feb1312, 09:15 AM

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#16
Feb1312, 10:03 AM

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Hey Guys,
I have given this a fair bit of thought so here goes: In order to have an EXACT duplicate of Earth, and when I say exact I infer identicality down to the configuration of individual atoms. That being said the Earth is being constantly bombarded by photons from our own hubble volume (in various EM wavelengths.) That being the case an identical Earth2 would need to exist in an identical hubble volume for Earth2 to be identical to Earth, within an identical Milkyway2. An exact duplicate of Earth cannot exist unless it exists in an exact duplicate of Milkyway.. ad infinitum until we are at the hubble volume size and causal disconnection takes effect. EDIT: Saw Cepheids post outlining this above after my post. (Post 13) It is possible to take a small amount of finite states and give an infinite amount of time and never repeat the same initial states so equally possible that an infinite amount of initial states over a finite time do not repeat the same configurations. The whole idea of another world with another me and everything the same... for some reason I just cannot accept that even an infinite Universe would repeat the same configuration exactly., although in fairness the Universe does not require my acceptance. 


#17
Feb1312, 10:20 AM

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#18
Feb1312, 07:42 PM

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