Based on this theory there is now believed to multiple dimensions, maybe as many as 10 or more! We are familiar with 4 dimensions----length, width, height and time, but there are more that we cannot perceive.
We know that God live outside of time---He is eternal and He has told us that to Him a day is like 1,000 years and 1,000 years is like a day. So I think this is His way of telling us that he exists in a different dimension, which is outside of time.
That is how I think it is for us. We, in our world of 4 dimensions, are like these prisoners watching the shadows on the wall. When we die and enter the eternal world of Heaven (or Hell) it will be like turning around and seeing reality rather than the shadows on the wall. We will see these other dimensions, we will be allowed to exist in them, outside of time, with God. How amazing will that be!
I have also read many stories of people on their death bed, surrounded by family. In the moments before their death, the person tells their family things that they see, that the family cannot see. The may say they see Heaven, or Jesus, or loves ones, or a bright light, a beautiful garden. All the family sees is the ceiling! I think perhaps upon the moment of our death, these other dimensions appear to us---like a portal--and our soul leaves our bodies and the confines of these 4 dimensions, and go to our true home with our Lord.
I also think that it is in these alternate or parallel dimensions that angels and demons exist and can be among us, but be invisible to us. I think this is basically told to us in 2 Kings 6: 17 when the King of Syria was trying to catch Elisha the prophet, he surrounded the city where Elisha was with a large army. Elisha's servant was scared but Elisha prayed, "O LORD, open his eyes so he may see." Then the LORD opened the servant's eyes, and he looked and saw the hills full of horses and chariots of fire all around Elisha.
Based on my readings and this verse, I am convinced that there are angels and demons around us that we are unable to see or sense and may even be fighting for our mortal souls, trying to lead us towards or away from God.