<p>We don't and can't <strong>know</strong> anything about the <em>un</em>observable universe.</p>
<p>The unobservable universe is very much like &quot;the future&quot;.  We don't know what will happen in the future (nor even if the future exists), but it is reasonable to suppose that the future will be very much like the past, at least at a physical level.</p>
<p>We don't know that it exists; if it does exist, we don't know if it has the same properties at any scale as the observable universe.</p>
<p>We also don't know that it is different from the observable universe in any significant way.</p>
<p>And finally at some very deep level, it doesn't matter.  Nothing that happens in the unobservable universe can affect us now.</p>
<p>It could affect us in the future, and here we can apply some inductive reasoning: The parts of the universe that were previously unobservable, but which we can now see are the same, in every significant way, to the observed universe.  As more of the universe has become observable, it has remained homogeneous and isotropic.  And this has continued for nearly 14 billion years.  It is reasonable to suppose that this will continue.</p>
<p>We don't know what the future will bring. We don't know what the unobservable universe contains. But it is reasonable to believe that the answer to both questions is &quot;more of the same&quot;.</p>

CC BY-SA 4.0
2024-09-13T21:49:27.907Z
Just what I was looking for, thanks
Ken - Enough about Monica
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2024-09-13T19:51:06.417Z
2024-09-13T19:51:06.417Z
James K
<p>I wonder hypothetically if it could be that we are (for example) part of a dust cloud blowing down the street in some huge town.  We know that in the observable universe there are objects that are very large and very small (from our perspective).  Can we know that beyond the observable universe, the scale of objects remains about the same?  That it can't blow up in scale immensely at some point?</p>

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2024-09-13T07:10:50.087Z
If you don't follow the reasoning until the evidence to the contrary that physics is universal and the universe homogen and isotropic at large scales, then anything is possible where we cannot look - and we are very suddenly in the field of religion instead of science, thus off-topic here. See also the antropic principle and occam's razor.
planetmaker
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2024-09-13T09:00:52.267Z
I’m voting to close this question because it's not about Astronomy.
Rory Alsop
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2024-09-13T10:37:18.393Z
Related: https://astronomy.stackexchange.com/a/32458/16685
PM 2Ring
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2024-09-13T18:45:06.303Z
@planetmaker why religion and not philosophy?
Ken - Enough about Monica
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2024-09-14T09:42:07.303Z
+1, not because the question looks good but because it has been proved that it can have a good physics based (and astronomy based) answer.
Pere
<observable-universe>
Is it possible that we are part of a relatively small object adjacent to a very large one?
Ken - Enough about Monica
# Is it possible that we are part of a relatively small object adjacent to a very large one?

(Asked by: username_0 on 2024-09-13)

I wonder hypothetically if it could be that we are (for example) part of a dust cloud blowing down the street in some huge town. We know that in the observable universe there are objects that are very large and very small (from our perspective). Can we know that beyond the observable universe, the scale of objects remains about the same? That it can't blow up in scale immensely at some point?

**Tags:** observable-universe

> **Comments:**
> **username_1**: If you don't follow the reasoning until the evidence to the contrary that physics is universal and the universe homogen and isotropic at large scales, then anything is possible where we cannot look - and we are very suddenly in the field of religion instead of science, thus off-topic here. See also the antropic principle and occam's razor.  
> **username_2**: I’m voting to close this question because it's not about Astronomy.  
> **username_3**: Related: https://astronomy.stackexchange.com/a/32458/16685  
> **username_0**: @username_1 why religion and not philosophy?  
> **username_4**: +1, not because the question looks good but because it has been proved that it can have a good physics based (and astronomy based) answer.  

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## 1 answers

### Answer by username_5 on 2024-09-13. Score: 6 | Accepted answer

We don't and can't **know** anything about the *un*observable universe.

The unobservable universe is very much like "the future". We don't know what will happen in the future (nor even if the future exists), but it is reasonable to suppose that the future will be very much like the past, at least at a physical level.

We don't know that it exists; if it does exist, we don't know if it has the same properties at any scale as the observable universe.

We also don't know that it is different from the observable universe in any significant way.

And finally at some very deep level, it doesn't matter. Nothing that happens in the unobservable universe can affect us now.

It could affect us in the future, and here we can apply some inductive reasoning: The parts of the universe that were previously unobservable, but which we can now see are the same, in every significant way, to the observed universe. As more of the universe has become observable, it has remained homogeneous and isotropic. And this has continued for nearly 14 billion years. It is reasonable to suppose that this will continue.

We don't know what the future will bring. We don't know what the unobservable universe contains. But it is reasonable to believe that the answer to both questions is "more of the same".

> **Comments:**
> **username_0**: Just what I was looking for, thanks  

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