/sci/ - Science & Math

[Anonymous No.8098234]

So, I've a question about astronomy, or quantum mechanics, I guess. Given the incredible size of our own universe, would it even be plausible for there to be theoretical billions of them, with some being exact replicas of our very own?

[Anonymous No.8098245]

>>8098234

Yes. This has been recognized for some time now.

[Anonymous No.8098252]

>>8098234
There is a probability that you are as you are. It's small but it exists. Call this P(you). The expected amount of you's to exist is the amount of events multiplied by the P(you).

In an infinite universe with an infinite amount of stuff which is clustered in a way that's similar to our local region and the stuff obeys the same rules of physics as our own. Let each cluster of stuff be an event with the possibility of you existing then doing crude math you can see that:
P(you) * #(events) = P(you)*infinity = infinity
thus you would expect an infinite amount of copies of yourself. You can refine what the criteria for P(you) are but shit's the same.

Since our observable universe is finite in size anything outside this finite region is merely speculation.

[Anonymous No.8098264]

...Why would size be a problem?

I mean what would prevent them to be big?... I don't understand the question here.

[Anonymous No.8098284]

>>8098252
>Since our observable universe is finite in size anything outside this finite region is merely speculation.
Ah, I see. That's where I had it wrong, I had thought that there simply wouldn't be, how can I put it, duplicates of the same combinations or arrangement of atoms.

[Anonymous No.8098343]

>>8098234
>Given the incredible size of our own universe, would it even be plausible for there to be theoretical billions of them
if by size you mean spatial dimensions\ 'volume' then i dont see how the size of the universe has any thing to do with all the other universes .

what is completely implausible is that if there are other universes that there are billions of them . it is far more plausible that there are 0 or infinitely many other universes .

we dont know what other universes 'existing' even means since we define existence as being at some point in space and time in THIS universe .and if there's other universes we cant know how they differ from ours (spacial dimensions\geometry , fundamental forces , particles , maybe they're exactly like ours with different 'constants').

[Anonymous No.8098359]

>>8098234
>the incredible size of our own universe
its size seems credible to me,
what do you find incredible?

[Anonymous No.8098371]

>>8098234
Was searching my database for this paper for a while OP, but I finally found it. Here's an excerpt from a paper by Max Tegmark:

Part I
Is there another copy of you reading this article, deciding to put it aside without finishing this sentence while you are reading on? A person living on a planet called Earth, with misty mountains, fertile fields and sprawling
cities, in a solar system with eight other planets. The life of this person has been identical to yours in every respect { until now, that is, when your decision to read
on signals that your two lives are diverging.
You probably find this idea strange and implausible, and I must confess that this is my gut reaction too. Yet it looks like we will just have to live with it, since the simplest and most popular cosmological model today predicts
that this person actually exists in a Galaxy about 10**10**29 meters from here. This does not even assume speculative modern physics, merely that space is infinite and rather uniformly filled with matter as indicated by recent astronomical observations. Your alter ego is simply a prediction of the so-called concordance model of cosmology,
which agrees with all current observational evidence and is used as the basis for most calculations and simulations presented at cosmology conferences. In contrast, alternatives
such as a fractal universe, a closed universe and a multiply connected universe have been seriously challenged by observations.

[Anonymous No.8098380]

Part II

The farthest you can observe is the distance that light has been able to travel during the 14 billion years since the big-bang expansion began. The most distant visible objects are now about 4x10**26 meters away, and a sphere of this radius defines our observable universe, also called our Hubble volume, our horizon volume or simply our universe. Likewise, the universe of your above-mentioned twin is a sphere of the same size centered over there, none of which we can see or have any causal contact with yet. This is the simplest (but far from the only) example of parallel universes.

Source: Max Tegmark, From Quantum to Cosmos, honoring John Wheeler's 90th birthday,
J.D. Barrow, P.C.W. Davies, & C.L. Harper eds., Cambridge University Press (2003)

[Anonymous No.8098841]

>>8098371
>>8098380
Ahh, this cleared it up for me. Thanks anon, I had previously thought that with an infinite number of universes, that eventually these multiple universes would collide, so to speak. While it is more plausible for there to be either our single universe, or an infinite amount of them, would they ever "collide"? If space is infinite, then me thinking that seems dumb of me. But, I guess the first question I should've asked is with an infinite number of universes, would our very own collide with another universe, perhaps?

[Anonymous No.8098861]

>>8098841
What do you think universe means?

[Virtual simulation No.8098870]

>>8098234
I keep having to teach anons,the universe isn't infinite because its expanding,if it were infinite it wouldn't need to expand.

[Anonymous No.8098871]

Billions of universes

[Anonymous No.8098885]

>>8098861
Universe has the prefix "uni" which means one, or single. But do we know if there is another, and whether it is an exact replica or not?

[Virtual simulation No.8098932]

>>8098885
You know sweet fuck all.

[Anonymous No.8098951]

>>8098234
>theoretical billions of them, with some being exact replicas of our very own?
Billions?

The observable universe is 46.6 billion light years in radius.
A Planck length is the shortest distance that matters (1.6 x 10-35 m).
That's a ratio of 2.75 * 10^61.
Even if there were only two particles in the entire universe, the odds of some other universe having those same two particles the same distance apart is absurdly unlikely.
And in reality, there are about 10^80 atoms in the observable universe.

[Anonymous No.8098958]

>>8098234
Not in the observable universe, be sure. If the observable universe is only a tiny portion of the whole universe, then yes, there could be copies outside the observable universe. But it's kind of an empty question because we, by definition, are not in causal contact with anything outside the observable universe so there's no way of verifying it.

[Anonymous No.8098967]

>>8098958
>>>8098234 (OP) (You)
>are not in causal contact with anything outside the observable universe so there's no way of verifying it.
The observable universe. If two universes were to collide, even if it may not be possible, would they merge just like two galaxies when they collide? And with this collision, would we even be able to notice it, despite it not being in the observable universe? If not, then there may be collisions happening this very moment, no?

[Anonymous No.8098990]

You first have to define space, time and all forces within to a satisfactory degree of understanding.

Then you will either realize that is is possible, or completely unnecessary.

Protip: Multiverse theory is pseudoscience popsci. The universe is pretedermined. There was no time before the big bang. There is only one universe. Human biases due to the nature of entropy is no excuse for poor science. Humanity is an embarrassment.

[Anonymous No.8099300]

>>8098359
>wow you're such a fool for using the word incredible and not meaning it literally