Hey Alex and Ralbert,
Good debatable material there. Obviously thrashed out by experts without reaching a solid conclusion.
My own thoughts and facts I've heard:
The human brain is finite in size and capacity. it cannot fathom the concept of infinity effectively. It qualifies such concepts to satisfy itself when the thought emerges.
Going with Jen's comment,"
Ouch
my head hurts 

".
Is one way of dealing with the thought and its almost true.
Having said that, I find it difficult to grasp a number of ideas, concepts in the Universe. those ideas produced by scientists at times.
The Universe is finite? I agree with you Alex. What's beyond it? Hey! Someone else says there are other universes' out there.

This is the big one: Matter cannot be destroyed or created. Energy, the same. Interchangeable yes. Matter to energy and vice versa.
Gravity is a force which shifts apples and galaxies. Bends light. Where does the energy for such a powerful force come from? The mass of the body producing it does not change, temperature does not affect it, is it related to other energy or forces?
Energy and force are related. When a force acts on a body energy is produced. With gravity its kinetic and /or compression and then spectacular things happen. What is this gravity? Is it creating energy? Am I missing something here?
If there was an opposite gravity force from a body it would not exist in this universe. The bodies would repel each other to achieve an equilibrium.
I know the effects of gravity but where's it come from?
My brain hurts
Cheers Marty