Well we know nowadays that the universe isn’t infinite, but is expanding, and the speed of expanding is accelerating. We don’t know if that will keep accelerating, if the universe will keep expanding forever.
How can you know or prove something isn’t infinite if you haven’t even seen all of it yet? Isn’t proving it impossible? We could prove it to NOT be infinite, but it’s like proving the non-existence of something, you can’t really prove an edge doesn’t exist just because you haven’t seen one.
Well we know nowadays that the universe isn’t infinite, but is expanding, and the speed of expanding is accelerating. We don’t know if that will keep accelerating, if the universe will keep expanding forever.
How can you know or prove something isn’t infinite if you haven’t even seen all of it yet? Isn’t proving it impossible? We could prove it to NOT be infinite, but it’s like proving the non-existence of something, you can’t really prove an edge doesn’t exist just because you haven’t seen one.
Because of the cosmic microwave background.
Here, this covers it quite well on a very basic level https://www.space.com/33892-cosmic-microwave-background.html