My understanding is that your solar chakra will produce an inense sun like light on the astral when your advanced. I believe what the one guy said about there being nested layers of meaning to it. I think of the saying as above so below. I find that statement true all the time. The concepts keep repeating on many layers. Maybe similar to how mathematical laws repeat through out the universe so do spiritual laws? (Natural laws)
I never heard of it being a real place, astral or otherwise as the one poster said. I hope to hear more on that.