The earth is small.  If you build a scale model of the solar system the size of a football field, with the sun and one end and Neptune at the other (Pluto has been laid off as a planet) then the sun will be about the size of a ping pong ball and the earth will be the size of a poppy seed (and it will be about ten feet from the sun).  Jupiter is about the size of a pea at this scale.  Alpha Centauri is about four miles away.<p>And not only do you live on a poppy seed, you live on a very thin layer on the surface of this poppy seed.  Blow the poppy seed up to the size of a basketball and the habitable layer is about the thickness of a sheet of paper.