How can the universe keep on expanding if it's infinite?

[Aarav Sangar]

How can the universe keep on expanding if it's infinite? Expanding metal, like a cube of aluminium, has a surface area which forms a border for the matter contained inside. So the universe must have a border for the matter it contains.

 

[lekh2003]

I found a neat article discussing the subject, can't say about the credibility, but it seemed to explain it better than I ever could: http://curious.astro.cornell.edu/ab...t-is-the-universe-expanding-into-intermediate

 

[PeroK]

How can the universe keep on expanding if it's infinite? Expanding metal, like a cube of aluminium, has a surface area which forms a border for the matter contained inside. So the universe must have a border for the matter it contains.

You could do a big of reading on what an expanding universe really means. Try starting here:

http://www.phinds.com/balloonanalogy/

The universe, whether it is finite or infinite need not have a border.

 

[FactChecker]

It only has a border if you can get outside it. The nature of the universe is like the surface of a solid appears to a bug crawling on it. The bug can not get off the surface, so that dimension may as well not exist for it. The universe is like that for us, except that the dimension needed to get out of the universe really doesn't exist.

 

[anorlunda]

Thread locked. The OP is no longer on PF.