Age versus Size of the Universe

[Naty1]

In my next life I'd like to be right all the time...like my wife in this life!

 

[Johninch]

Well one CAN imagine being able to look out waaaaaay beyond the current 46bly sphere from which we receive the most distant light. why not...if Einstein could imagine catching up to light we can imagine an 'empty' portion of the universe.

It is generally accepted that the universe probably extends far beyond the 46 bly observable portion. I do not imagine being able to “look beyond” it, as you suggested, because that is impossible by definition.

I imagine being physically beyond it in another observable portion.

I wasn’t aware that it’s possible to catch up to light – please explain how “Einstein imagined catching up to light”.

I also don’t know what you mean by “an empty portion of the universe”. Do you mean a bubble? A bubble as large as our observable portion would offend the cosmological principle and wouldn’t be compatible with the CMBR measurements as far as I know.

If you mean an empty portion adjacent to a boundary, I don’t think this makes sense. On the one hand it would be merely changing the shape, i.e. ‘drawing in’ the boundary. On the other hand I am doubtful that there could be an empty portion at all. As far as I know, in modern cosmological theory there is no such thing as empty space. Please explain how “we can imagine an empty portion of the universe”.

To repeat, and I hope that I don’t have to repeat this again, my thought experiment was standing at a point in the universe, a long way outside of our observable portion. I look at the sky with the best instruments possible. In a big portion of the sky, say half of it, there is nothing to be observed. I would conclude that there is nothing in that direction and that the universe does not extend any farther in that direction.

There may in fact be a 'lack of galaxies' out, say 100 times or 1,000 or 10,000 times further than we can observe today. Nobody can prove that one way or another. But then you should have some reason for such a hypothesis.

It is not a hypothesis, it’s a question related to the geometry of the universe and whether it can be infinite or not. Marcus has given me good feedback, which you applauded, and I need to digest it, as he suggested. At the moment I am still stuck on the idea of a finite universe with a size and I still don’t accept an infinite one.

Trying to describe outside the universe is like trying to describe non existence. As many are pointing out.

Mordred: I think it is silly to try to describe outside the universe and/ or non-existence. So please don’t attribute these ideas to me.

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[Naty1]

It is generally accepted that the universe probably extends far beyond the 46 bly observable portion. I do not imagine being able to “look beyond” it, as you suggested, because that is impossible by definition.

Ah, but you can in fact see further each time you look!

Next year you will be able to see 'one additional light year' distant...
That's not an actual number but an illustration...But you can do calculations
using the Jorrie on line calculator and figure out such things for yourself...in fact just read Marcus' posts...he has already done many illustrative calculations.

check out the last few pages here for examples:

Look 88 billion years into future and see cosmic event horizon shaping up
https://www.physicsforums.com/showthread.php?t=634757&page=3

please explain how “Einstein imagined catching up to light”.

This was supposedly a 'thought experiment' when Einstein was a teenager...from it, he began his later work on special relativity...refuting the then popular 'aether' theory and instead taking as a given that the speed of light is the same for all intertial observer frames.

 

[Mordred]

No problem just wanted to make sure that all the comments on outside observation were merely a thought experiment.

 

[Johninch]

Ah, but you can in fact see further each time you look!

HaHa! Better than your wife joke!

.

 

[Naty1]

No joke.

You should READ the link so you understand.