If you don’t understand, you soon will. There are powerful forces at work in your life, keeping you down. Ever find yourself struggling to get up in the morning? Have you ever fallen and had difficulty getting back up?
Say hello to gravity. Gravity is everywhere, whether you like it or not. Everything that has mass has gravity. The more mass you have, the stronger your pull is on everything else. The Earth is very massive, hence you don't feel me pulling you from all the way over here, but that doesn't change the fact that I'm pulling. It's not mumbo jumbo (unless you believe that God's sneeze really did set everything in motion for me to be telling you this).
Yes, gravity is the reason you stick to the ground, “but how does a satellite stay in orbit," you ask? Well, there are other forces involved - let's just call this 'motion' for the sake of simplicity. It's ‘motion’ that keeps satellites and the moon from falling to the Earth, what keeps the Earth and other planets from falling into the sun, and what keeps the universe from collapsing (at least for now). Motion (all sorts of different kinds of force) acts against the force of gravity to keep gravity from winning the endless struggle to crush you. When you jump in the air, your motion temporarily beats gravity and you go up. If you have enough counter force, you can avoid falling back down.
At this point, you should have a basic understanding of this standard property of the universe. If you want more info, look it up. A .EDU website should be a good source; Yahoo Answers is not. If you still don’t believe that gravity is everywhere, go back to grade school. Here’s a site explaining the same as above (with more detail) targeted at children.