How can you imagine this universe ?
Universe can be thought of a volume with no borders......
It is a nice idea to think of......
We human beings are limited to volume.....what it means ..? Here is the explanation.....
Think of a creature which is limited to an Area...If that creature is allowed to move around a sphere surface...It feels the area is unlimited.....
Sphere exists in a
volume..that the creature which is limited to
area is unaware of.....
Same applies to us..we are limited to volume..may be this universe exists on a 4 dimensional sphere(n-sphere). This concept opened a lot of new possibilities..but still no real progress other than speculations...
We may be able to explain complex properties in 3-Dworld with simple equations in a 4-D world.