How can an infinite universe be expanding?

[Ben.meyer]

I have been looking around people are talking about the universe expanding. By geometry we are able to figure out that the universe is infinite. The question is, if the universe is infinite than how can be expanding?

 

[phinds]

I have been looking around people are talking about the universe expanding. By geometry we are able to figure out that the universe is infinite. The question is, if the universe is infinite than how can be expanding?

No, we are NOT able to calculate that the universe is infinite. It MIGHT be, or it might not be.

Regardless, if it IS infinite, then continued expansion is not a problem.

You should read up on the concept of infinity.

 

[nicksauce]

Imagine I have a set 1,2,3,4,5,6,...

Then some later time that set has now 2,4,6,8,10,12,...

Both sets are infinite, but in some sense that set has expanded.

 

[Ben.meyer]

Thanks, that definitely gave me a better understanding.