# There cannot possibly be an "edge of the Universe." **URL:** \ **Category:** Great Debates\ **Created:** [July 9, 2025, 1:51am UTC](https://boards.straightdope.com/t/there-cannot-possibly-be-an-edge-of-the-universe/1020649 "2025-07-09T01:51:43Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![Clu-Me-In](https://avatars.discourse-cdn.com/v4/letter/c/dfb087/32.png) [@Clu-Me-In](https://boards.straightdope.com/u/Clu-Me-In)\ **Post date:** [July 9, 2025, 1:51am UTC](https://boards.straightdope.com/t/there-cannot-possibly-be-an-edge-of-the-universe/1020649/1 "2025-07-09T01:51:43Z")
If the Universe is expanding faster than the speed of light, how can we humans keep saying or referring to the edge of the Universe? ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [July 9, 2025, 1:55am UTC](https://boards.straightdope.com/t/there-cannot-possibly-be-an-edge-of-the-universe/1020649/2 "2025-07-09T01:55:10Z")
Because human speech isn’t constrained by scientific fact. That said, scientists might refer to the edge of the _observable_ universe, which is defined by that same speed of light; it’s how far we can _see,_ not the physical edge of the universe. ---
**Author:** ![Clu-Me-In](https://avatars.discourse-cdn.com/v4/letter/c/dfb087/32.png) [@Clu-Me-In](https://boards.straightdope.com/u/Clu-Me-In)\ **Post date:** [July 9, 2025, 1:56am UTC](https://boards.straightdope.com/t/there-cannot-possibly-be-an-edge-of-the-universe/1020649/3 "2025-07-09T01:56:16Z")
There is no edge to the observable universe. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [July 9, 2025, 1:57am UTC](https://boards.straightdope.com/t/there-cannot-possibly-be-an-edge-of-the-universe/1020649/4 "2025-07-09T01:57:43Z")
Of course there is, that’s what the term _means;_ it’s how far we can observe anything. It’s at edge the same way the horizon is an edge. ---
**Author:** ![Dissonance](https://avatars.discourse-cdn.com/v4/letter/d/85f322/32.png) [@Dissonance](https://boards.straightdope.com/u/Dissonance)\ **Post date:** [July 9, 2025, 1:57am UTC](https://boards.straightdope.com/t/there-cannot-possibly-be-an-edge-of-the-universe/1020649/5 "2025-07-09T01:57:51Z")
I dropped my glass of water on the floor. The spill is still currently expanding. How can we humans possibly refer to the edge of my spilled water when it is expanding? ---
**Author:** ![Clu-Me-In](https://avatars.discourse-cdn.com/v4/letter/c/dfb087/32.png) [@Clu-Me-In](https://boards.straightdope.com/u/Clu-Me-In)\ **Post date:** [July 9, 2025, 1:58am UTC](https://boards.straightdope.com/t/there-cannot-possibly-be-an-edge-of-the-universe/1020649/6 "2025-07-09T01:58:32Z")
Who observed this edge you speak of? ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [July 9, 2025, 2:01am UTC](https://boards.straightdope.com/t/there-cannot-possibly-be-an-edge-of-the-universe/1020649/7 "2025-07-09T02:01:44Z")
Astronomers. ---
**Author:** ![Clu-Me-In](https://avatars.discourse-cdn.com/v4/letter/c/dfb087/32.png) [@Clu-Me-In](https://boards.straightdope.com/u/Clu-Me-In)\ **Post date:** [July 9, 2025, 2:11am UTC](https://boards.straightdope.com/t/there-cannot-possibly-be-an-edge-of-the-universe/1020649/8 "2025-07-09T02:11:13Z")
The same astronomers that agree that the Universe is expanding and expanding faster than the speed of light? ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [July 9, 2025, 2:13am UTC](https://boards.straightdope.com/t/there-cannot-possibly-be-an-edge-of-the-universe/1020649/9 "2025-07-09T02:13:27Z")
Yes? There’s no conflict there. ---
**Author:** ![Clu-Me-In](https://avatars.discourse-cdn.com/v4/letter/c/dfb087/32.png) [@Clu-Me-In](https://boards.straightdope.com/u/Clu-Me-In)\ **Post date:** [July 9, 2025, 2:18am UTC](https://boards.straightdope.com/t/there-cannot-possibly-be-an-edge-of-the-universe/1020649/10 "2025-07-09T02:18:30Z")
Do you agree with them and therefore see no obvious thought anomaly or are you stalling for a more appropriate response? ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [July 9, 2025, 2:25am UTC](https://boards.straightdope.com/t/there-cannot-possibly-be-an-edge-of-the-universe/1020649/11 "2025-07-09T02:25:51Z")
> [@Clu-Me-In](#): > > If the Universe is expanding faster than the speed of light, how can we humans keep saying or referring to the edge of the Universe? > **[Cosmological horizon](https://en.wikipedia.org/wiki/Cosmological_horizon)** > > A cosmological horizon is a measure of the distance from which one could possibly retrieve information. This observable constraint is due to various properties of general relativity, the expanding universe, and the physics of Big Bang cosmology. Cosmological horizons set the size and scale of the observable universe. This article explains a number of these horizons. > The particle horizon, also called the cosmological horizon, the comoving horizon, or the cosmic light horizon, is the maximum dista... Stranger ---
**Author:** ![FlikTheBlue](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fliktheblue/32/10972_2.png) [@FlikTheBlue](https://boards.straightdope.com/u/FlikTheBlue)\ **Post date:** [July 9, 2025, 2:31am UTC](https://boards.straightdope.com/t/there-cannot-possibly-be-an-edge-of-the-universe/1020649/12 "2025-07-09T02:31:04Z")
I thought the reason there can’t be an edge is due to translation symmetry. If there’s an edge, that means that there is (a) / are privileged place(s). If that was the case, then experiments done at those places would give different results than experiments done in other places. If this was the case, then the corresponding conservation law, the conservation of momentum, wouldn’t hold, and since it does, that means we can know that there is no edge (or center). ETA: Which doesn’t necessarily mean the universe is infinite in any of the spatial dimensions. It’s possible for the universe to be finite in size but still have no edge. ---
**Author:** ![Clu-Me-In](https://avatars.discourse-cdn.com/v4/letter/c/dfb087/32.png) [@Clu-Me-In](https://boards.straightdope.com/u/Clu-Me-In)\ **Post date:** [July 9, 2025, 2:31am UTC](https://boards.straightdope.com/t/there-cannot-possibly-be-an-edge-of-the-universe/1020649/13 "2025-07-09T02:31:57Z")
I read that before postings. I consider it mumbo jumbo cos it truly falls into the circular reasoning theory. It’s rubbish. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [July 9, 2025, 2:44am UTC](https://boards.straightdope.com/t/there-cannot-possibly-be-an-edge-of-the-universe/1020649/14 "2025-07-09T02:44:52Z")
It is the scientific consensus by cosmologists backed up by extensive astronomical observations and our well-validated theory of gravitation (general relativity). Are you actually trying to ask a question and solicit discussion, or [are you just here for an argument](https://youtu.be/ohDB5gbtaEQ?si=RqL6EVIBAzB_ghPS)? Stranger ---
**Author:** ![scabpicker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/scabpicker/32/8268_2.png) [@scabpicker](https://boards.straightdope.com/u/scabpicker)\ **Post date:** [July 9, 2025, 2:47am UTC](https://boards.straightdope.com/t/there-cannot-possibly-be-an-edge-of-the-universe/1020649/15 "2025-07-09T02:47:33Z")
> [@FlikTheBlue](#): > > ETA: Which doesn’t necessarily mean the universe is infinite in any of the spatial dimensions. It’s possible for the universe to be finite in size but still have no edge. Ya know, maybe a doughnut. Or maybe three of them. > **[3-torus](https://en.wikipedia.org/wiki/3-torus)** > > The three-dimensional torus, or 3-torus, is defined as any topological space that is homeomorphic to the Cartesian product of three circles, > > > > > > T > > > 3 > > > = > > S > > 1 > > > × > > S > > 1 > > > × > > S > > 1 > > > . > > > ... ---
**Author:** ![Aspenglow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aspenglow/32/76_2.png) [@Aspenglow](https://boards.straightdope.com/u/Aspenglow)\ **Post date:** [July 9, 2025, 2:50am UTC](https://boards.straightdope.com/t/there-cannot-possibly-be-an-edge-of-the-universe/1020649/16 "2025-07-09T02:50:14Z")
Moderating: > [@Clu-Me-In](#): > > I read that before postings. I consider it mumbo jumbo cos it truly falls into the circular reasoning theory. It’s rubbish. I’m not seeing a good faith effort at debate here. The OP was dubious, but I was willing to see where the discussion went. Based on the above post, however, I’m convinced the OP is not here for a reasoned discussion. Accordingly, this is closed. ---
**Author:** ![Aspenglow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aspenglow/32/76_2.png) [@Aspenglow](https://boards.straightdope.com/u/Aspenglow)\ **Post date:** [July 9, 2025, 2:50am UTC](https://boards.straightdope.com/t/there-cannot-possibly-be-an-edge-of-the-universe/1020649/17 "2025-07-09T02:50:22Z")