# Why are we locked into 3-D space if universe if 4-(or-more)-D?

**URL:** <https://boards.straightdope.com/t/why-are-we-locked-into-3-d-space-if-universe-if-4-or-more-d/698262>\
**Category:** Factual Questions\
**Created:** [September 12, 2014, 5:03am UTC](https://boards.straightdope.com/t/why-are-we-locked-into-3-d-space-if-universe-if-4-or-more-d/698262 "2014-09-12T05:03:08Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\
**Post date:** [September 12, 2014, 5:03am UTC](https://boards.straightdope.com/t/why-are-we-locked-into-3-d-space-if-universe-if-4-or-more-d/698262/1 "2014-09-12T05:03:08Z")

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I’ve long wondered about this. I’m sure it’s a very trendy thing to wonder about.

Now, spurred to action by [this post](http://boards.straightdope.com/sdmb/showpost.php?p=17723570&postcount=9) in [this thread](http://boards.straightdope.com/sdmb/showthread.php?t=733885), I’m asking here.

> [@2D/3D holographic universe/vision](https://boards.straightdope.com/t/2d-3d-holographic-universe-vision/698215/9):
>
> We really do live in and experience a world with three spatial dimensions. All physicists agree on that. The holographic cosmology models, however, posit that the three-dimensional Universe that we experience is a holographic projection from a two-dimensional universe which is more fundamental. **Meanwhile, there are also other models that posit that our Universe is actually just one slice of a higher-dimensional universe of some sort, with some sort of mechanism (there are a variety posited) preventing us from perceiving the extra dimensions.**

If there are more dimensions “out there”, of which our known Universe is just a slice, what keeps us confined to our slice? What are some of the posited mechanisms? (More-or-less Dummy-level explanations, please.) I know of suggestions that there may be some extra “compact” dimensions laying around. But aside from that, are there models of the Universe with additional “large” dimensions?