<blockquote><font class="small">In reply to:</font><hr /><p>i'm talking from a height above the ground that is not in orbit.<p><hr /></p></p></blockquote><br /><br />Minor quibble: being in orbit is determined by your trajectory (in particular, your velocity), not by your altitude. Theoretically, an object could be in orbit at an altitude of a foot, but it would surely run into things. <img src="/images/icons/wink.gif" /> (And of course the fact that the Earth's mass is not perfectly distributed will have a profound effect at such close range.)<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>there is no difference between acceleration upon objects and gravity. they are one and the same. <p><hr /></p></p></blockquote><br /><br />They can be treated the same, but although all gravitational fields produce acceleration, not all acceleration is due to gravity. The transitive property of equality does not apply in this situation.<br /><br />It is true that you could, with some serious mathematical calisthenics, produce a model where gravity is actually the Earth's material accelerating outwards. After all, as we well know, everything is relative and no frame of reference is to be preferred, therefore it's valid to do this. Not neccesarily sensible, but valid. But this will get far more complicated than I think you expect. Your model will have to explain why the trajectory of a passing object is deflected by a large mass if there is no force acting between them, and produce mathematical equations to predict this. (In short, you'll need to derive the classic gravity equations from your model, and that won't be easy.) In fact, the mathematics may be insoluble.<br /><br />A similar problem faced Renaissance astronomers such as Tycho Brahe, who were attempting to derive equations which would predict the motion of the planets in a geocentric solar system. They were getting close, but it seemed that with each advance, the model simply got more complicated. Reading the history of <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em> -- The Tenth Doctor, "Blink"</font></p> </div>