>> Why do you need more than one dimension for time coordinates to express time dilation Because in theory, there is no absolute time we can take as reference. 1 year for an object on moon is not 1 year for an object on Jupiter. So time dimension may include other factors that defines itself.

>> How is time an outcome of gravity?!? "General relativity shows that gravity is really not a force, but rather a consequence of the fact that space-time is curved due to the distribution of mass and energy." More on http://www.ram.org/ramblings/science/time_is_relative.html