From the syllabus — Reading: Find and read descriptions of Einstein’s Theory of General Relativity and how it relates to time. Describe it in your own words on your blog and post a link to it on the wiki. We’ll go through your descriptions in class. How would you describe it to a 5 year old or your grandmother?
Nothing can go faster than the speed of light, and this restriction applies to influences (such as the force of gravity) between massive elements (planets, particles, people) in the universe. It is these forces that determine the movement of objects, the swinging of a pendulum in a clock, the workings of our consciousnesses, and the travel of light.
When the objects in question are moving with respect to some other perceiving entity, the things traveling between the moving objects have to travel slightly further because the destination object will have moved further away from the original point of the source object by the time the things moving between them can arrive. It follows that those things then have to either travel faster or take longer to get there. If those things are already traveling at the speed of light (such as influence due to gravity), then they cannot go any faster, so they must take longer, and the interactions between the moving objects slow from the point of view of the outside observer.
The moving object, however, still behaves just as it did before, albeit slightly more slowly. Because the workings of its own ability to perceive time — either with a clock, or with a human consciousness, or with something else — have all slowed down in precisely the same fashion, the moving object experiences time just as it did before.
Particularly useful sources:
- http://www.physics.fsu.edu/Courses/Spring98/AST3033/Relativity/GeneralRelativity.htm — “When later it became clear that influences travel at finite speeds it was reasonable to suppose this true of gravity also.”