<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Thus the potential has its largest negative value at the center and you are right the clocks tick the slowest. I think that would correctly be described as the minimum time dilation. The maximum dilation is as the distance from the sphere itself approaches infinity and the potential approaches 0 and the clocks tick the fastest. <br /> Posted by UncertainH</DIV></p><p>I would have it the other way round, if you want to think of it in terms of the clock that ticks the fastest or slowest.</p><p>The "fastest" clock would be a clock in free-fall in deep space, the furthest from any massive object. The "slowest" clock would be a clock at the event horizon of a black hole. The conditions on the surface of the Earth, or even at its centre, are far closer to the "fastest" clock than they are to the "slowest" clock.</p><p>The <em>arrow of time</em> should define the any "direction" we want to frame around time-dilation. Time moves in only one direction - forwards.</p><p>Only from the frame of reference where the clock is "fastest", where <em>every other</em> clock in the universe seems to be running slower than themselves, is there no time-dilation. Time runs at its baseline rate in empty space. Introduce mass or energy into that space, and you start dilating time when compared to that baseline!</p><p>(This post is not meant in any way to imply any notion of absolute time (which might only be possible in a truly empty universe) and ignores time-dilation due to 1: the expansion of the universe. 2: Having to move a clock at relativistic speeds to get it out of the Virgo Cluster. Also, all clocks tick at the same rate, a second per second. The difference in any <em>apparent</em> clock rate between yours and someone elses frame of reference is due to the difference in the frames of reference and their notions of simultaneity, which is ultimately due to their respective paths through space-time).</p><p><img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-wink.gif" border="0" alt="Wink" title="Wink" /> </p> <div class="Discussion_UserSignature"> <p><font color="#ff0000">_______________________________________________<br /></font><font size="2"><em>SpeedFreek</em></font> </p> </div>