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> There is also no way to disprove that without observing beyond the universe, which may get a bit dicey. My high school physics prof had the best answer to "W
by Swizec 9y ago
> There is also no way to disprove that without observing beyond the universe, which may get a bit dicey.
My high school physics prof had the best answer to "What is beyond the universe?" --> "Surely if we ever find something outside of the universe, we will be smart enough to call that the universe too"
He was referencing the idea that universe contains everything by definition.
- jfaucett 9y agoThats a clever but not very mathematical answer. The general problem here is the conflation of universe i.e. "all of spacetime and everything we will ever discover" with the idea of a universal set, which doesn't have to include all elements and is rather arbitrary/relative.
- olegkikin 9y agoIn terms of definitions, generally cosmos contains everything. Universe is our local observable space-time with the earliest event we can detect being the big bang.
- Swizec 9y ago> Universe is our local observable space-time So if we observe something beyond what is currently observable, would that not become observable and thus part of the universe?
- alansammarone 9y agoYes, but it might also be the case that we don't observe something outside of it, but rather infer the existence of something outside of it through some other phenomenon (which is much more probable - observing something outside of the visible universe as we know it would violate relativity). In that sense, it would be there, but would never be visible.
- Swizec 9y agoThat's a really interesting question. If something is indirectly observable (you can observe/measure its effect), does that make it observable or not? Transitivit would say yes. If A implies B and B implies C then A implies C. That is, if you can observe A and that implies B, then you can observe B. Which makes it observable, no?
- barrkel 9y agoAll observations are inferences from indirect phenomena.
- olegkikin 9y agoYou're in a room. You give it label "room". Then you find a door, you go outside of the room, you don't call everything outside "room", you give new things new names. For now we're stuck in our universe, we know it's expanding (in something, potentially). So we preemptively give the name "cosmos" to EVERYTHING. It's entirely possible that cosmos is equal to universe. But it's also possible there are other universes out there, or something entirely different.
- LambdaComplex 9y agoIn your scenario, the door is a clear divider between "room" and "not room." What's the equivalent divider in the universe scenario?
- cmiller1 9y agoThe term observable when used in the context of the observable universe doesn't necessarily mean something we can actually measure or look at, but rather that which could theoretically have interacted with anything we could interact with based on the speed of light, the age of the universe, and cosmic expansion. Think of it as a bubble of time and everything outside of it hasn't happened yet.