Gravitational Time Dilation
An important aspect of Einstein's theory of relativity to note is that he proposed matter causes space to curve. If we pretend that "space" is a two-dimensional sheet, a planet place on this "sheet" would cause it to curve (see diagram below). This curvature of space results in what we perceive as gravity. Smaller objects are attracted to larger onesbecause they "roll" through the curved space towards the most massive objects, which cause the greatest degree of curvature. In relation to time, this curvature causes the gravitational time dilation effect. Under normal circumstances, this effect is impossible to observe. However, in the presence of the extremes of our universe (such as black holes, where a huge amount of matter is compressed into an extremely small volume), this effect becomes much more obvious. To a distant observer, an object falling into a black hole would appear to never reach it, due to time dilation causing time to "progress" extremely slower, at least relative to the distant observer (the object in question,