Why is the universe expanding?
I crumble up a piece of paper into a ball and fire it up. As it is burning, the flame catches my fingers, I throw it at a wall. “WOW!” I yell. The sparkles flying all over. Some brightly lit while others slowly dim and disappear within a second. At the impact, everything is pushed against the wall; therefore, the universe is expanding FAST in ONE DIRECTION.
What is the paper made out of?
I’m sure it contains a variety of biological and chemical substances; such as iron, oxygen, hydrogen, and whatever and even my own DNA. Imagine one of those flying ashes is a galaxy and so forth… now you can picture how the universe and our planet are formed. The living thing on that planet calls me GOD, but doesn’t really know I exist based on “seeing is believing”. I don’t know I created such a living thing. If I did, who’d care? Those sparkles last only for a few seconds, so who cares…
Dark matter? the stuff needed to make the paper.
Dark Energy? it takes guts and effort to crumble up a piece of paper into a ball, fire it up and throw it at the wall.
Black hole? every size of explosion has its own size of black hole.

There is that WALL!

Read More http://www.wired.com/geekdad/2010/01/stephen-hawking-to-take-us-into-the-universe/#ixzz0mBB8NbCp