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Universe

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Prof Wind Up Merchant
1412522.  Mon Jun 06, 2022 2:16 pm Reply with quote

Is it infinite or not?

We have only observed objects a finite distance away but space must go on forever.

 
PDR
1412526.  Mon Jun 06, 2022 2:35 pm Reply with quote

It can be both, depending on how many dimensions you use to describe it.

But however big it is I would say Surrey is at the centre of the observable universe.

PDR

 
Prof Wind Up Merchant
1412529.  Mon Jun 06, 2022 2:46 pm Reply with quote

PDR wrote:
It can be both, depending on how many dimensions you use to describe it.

But however big it is I would say Surrey is at the centre of the observable universe.

PDR


You are biased towards Surrey I see. Kind of giving away your neck of the woods.

:-D

 
PDR
1412530.  Mon Jun 06, 2022 2:53 pm Reply with quote

No, just a statement of fact. By definition wherever I am is the centre of my observable universe - it would be physically impossible for it to be otherwise.

PDR

 
Prof Wind Up Merchant
1412531.  Mon Jun 06, 2022 3:00 pm Reply with quote

That is disputed PDR.

 
PDR
1412535.  Mon Jun 06, 2022 3:07 pm Reply with quote

The centre of *your* observable universe is wherever you are at the time. The centre of *my* observable universe is wherever I am at the time. It's sort of implicit in the terms "centre" and "observable"

PDR

 
CB27
1412554.  Tue Jun 07, 2022 5:19 am Reply with quote

I would argue that the universe is both finite and infinite by it's very nature.

The universe is all of space and time, and you could "theoretically" reach the edge of the universe where time and space no longer exist, which makes it finite, but you can't "technically" reach the edge of the universe as you need time and space to be able to define it in the first place.

It kind of reminds me of the theoretical height it would take to drop a squirrel and kill it in post 1390060. There are technical differences to the theoretical calculations.

 
tetsabb
1412577.  Tue Jun 07, 2022 10:30 am Reply with quote

42

 
PDR
1412583.  Tue Jun 07, 2022 11:10 am Reply with quote

CB27 wrote:

The universe is all of space and time, and you could "theoretically" reach the edge of the universe where time and space no longer exist, which makes it finite,


I'm not aware of any theory that predicts the universe has such an edge, because that would immediately spawn the question as to what was beyond that edge. One could suggest that there was "nothing" beyond that edge, but as the overwhelming majority of the universe is comprised of "nothing" anyway it would become necessary to explain why the alleged "edge of the universe" had been deemed to be at that location when there w no distinguishing feature that said "this bit is inside the universe but that bit over there is not".

That's why the n-dimensional concepts which suggest the universe is only infinite in three dimensions because it is curled in on itself in higher dimensions are probably the simpler postulation (Occamly speaking).

PDR

 
PDR
1412584.  Tue Jun 07, 2022 11:10 am Reply with quote

CB27 wrote:

The universe is all of space and time, and you could "theoretically" reach the edge of the universe where time and space no longer exist, which makes it finite,


I'm not aware of any theory that predicts the universe has such an edge, because that would immediately spawn the question as to what was beyond that edge. One could suggest that there was "nothing" beyond that edge, but as the overwhelming majority of the universe is comprised of "nothing" anyway it would become necessary to explain why the alleged "edge of the universe" had been deemed to be at that location when there w no distinguishing feature that said "this bit is inside the universe but that bit over there is not".

That's why the n-dimensional concepts which suggest the universe is only infinite in three dimensions because it is curled in on itself in higher dimensions are probably the simpler postulation (Occamly speaking).

PDR

 
CB27
1412599.  Tue Jun 07, 2022 12:51 pm Reply with quote

Well, you're now aware of my theory :)

Is the universe full of nothing?

I understood that "nothing" is still space.

True "nothing" has neither space nor time, so when the universe is expanding, it's not replacing nothing.

I look at it like theoretical super elastic balloon made from material that will never burst, with no opening, with a specific gas that can expand, and does not exist outside the balloon.

You can expand the gas, and therefore the balloon, but it's not replacing any gas or space that existed outside the balloon. In this particular example, because there is a physical presence outside the edge of the balloon, you can technically reach the edge, for the universe it's a case of when space and time exists and when it doesn't. As we occupy time and space, and so do any equipment we use, we could never technically reach the edge because we're the ones actually stretching the universe.

 
crissdee
1412614.  Tue Jun 07, 2022 3:11 pm Reply with quote

I may have mentioned this before, but despite "knowing" for many years that the universe is "infinite", my brain still goes a bit woozy when I try to imagine the concept. The idea that if you had something such as the Bussard Ramjet, and could continue to travel as far as you wanted to, but you would NEVER reach any kind of "end", just blows what's left of my mind....

 
CB27
1412643.  Wed Jun 08, 2022 6:04 am Reply with quote

By it's very existence it's not reaching any end :)

 
Prof Wind Up Merchant
1412890.  Sat Jun 11, 2022 9:50 am Reply with quote

PDR wrote:
The centre of *your* observable universe is wherever you are at the time. The centre of *my* observable universe is wherever I am at the time. It's sort of implicit in the terms "centre" and "observable"

PDR


I am winding you up PDR. Living up to my name. :-D

 

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