reading all your very interesting messages and some of the emphasis on what we don't know made me think just what we don't know, for instance, Gravity, we don't really know what it is or how it really works, Oceans, there are theories where all that water came from but no definite answers to convince anyone, Lightning, does any one have a simple exclamation of how it works and how it is so powerful. There are so many mysteries in the universe that we will never understand and those that we think we do have no real substance, I think we are not made to understand them until later, but, gives us a lot to think about which is part of human nature. James Dixon.