To feel the impression of deep space, try this little field experiment sometime: walk out into a extremely large area at night (say a farmer's field) and look straight up into the blazing star-filled "dome" above you. No moon light allowed. Then start to convince yourself that your looking "out" instead of looking "up". Stay with it for a few moments and then convince yourself you're actually looking down instead - hanging off the ball of the planet peering into space... your feet and Earth all behind you. You may suddenly feel like you're falling (or not) but you might get the impression of the deepness of space all around us. In fact pause for a moment, and know that just above your head by maybe a milimeter or so, the entire universe stretches out into it's infinity.