How Time Slows Down as We Speed Up

Perhaps you have heard that the faster we go the slower time elapses. This phenomenon is so profound that satellites orbiting at fixed positions above Earth must take into account the difference in speed it travels to maintain that fixed position.

What is difficult to understand is that time really is moving at different speeds. It is not an illusion. If we remain on Earth, the clock on Earth would maintain time perfectly. If we were on the satellite, the clock on the satellite would maintain time perfectly.

That is so counter-intuitive that we may say we know it, but most of us do not try to figure out why it is so.

I have created a visual in graph form to show how this works: 

Understanding why I should take Word out of edit mode before taking a screen shot.

The graph above shows two planes beginning at the same relative time. The distance covered by a pulse of time catching up to something moving faster is greater. Once a pulse of time reaches something, another pulse of time begins. The image shows that in the distance that the pulse of time reaches the slower mass, it is only halfway to the speedier mass. 

In the distance it takes for one pulse of time to reach the speedier mass, the second pulse of time is reaching the slower mass. The slower mass will experience pulses of time at a ratio of 2:1.

We don’t really move on planes from axes on parallel lines. Also, the speed of light from either the slower mass or the faster mass is still the speed of light. It is all relative. However, the graph does show visually how time slows down as we speed up.