I'm studying basic physics involving reference frames and how they affect our perception of motion/time. I know that if I stand still and watch a car drive by it looks to be going fast; but if I run after it the speed of the vehicle may appear slower to me. If the ground has eyes, it would look like I'm going fast compared to the ground, and the vehicle even faster.

Thinking about this though, how do I know how fast I'm going? If the earth is in the solar system, the solar system moves within the galaxy, and the galaxy moves, what truly is time/motion?

Question

I'm studying basic physics involving reference frames and how they affect our perception of motion/time. I know that if I stand still and watch a car drive by it looks to be going fast; but if I run after it the speed of the vehicle may appear slower to me. If the ground has eyes, it would look like I'm going fast compared to the ground, and the vehicle even faster. 

Thinking about this though, how do I know how fast I'm going? If the earth is in the solar system, the solar system moves within the galaxy, and the galaxy moves, what truly is time/motion?

anonymous · Answer

in physics, to solve a problem one has always got to make an approximation somewhere, the approximation that we do most of the time is considering earth an inertial reference frame, but sometimes for example in long-range ballistics, they take into account coriolis apparent force, which exists because earth is not a truly inertial frame, it all depends on the level of accuracy that one needs.

No need to make motion a philosophical question :)

anonymous · Answer

That is fascinating, thanks for the response! I guess I'll just have to continue pursuing physics until some of these more complex topics make sense to me.