Good evening, mes amis, it is Professor Dubois once more. This will not be an extended talk, but I had on my mind the concept of frame of reference, or perspective, and I wished to share it with you.
You have heard it said that a body remains at rest or remains in motion unless acted upon by some outside force. Now, imagine two masses, shall we say, two baseballs, sitting on the floor. Neither is moving. They are not moving relative to each other, but they are moving, are they not? Could not this floor be falling from an airplane? Or from a spaceship over an airless planet? In that case, are not the balls accelerating in relation to the planet or moon toward which they are falling?
But the planet or moon where the balls are falling, or perhaps resting, is itself rotating, and it is revolving around a star, and that star is likely revolving around a supermassive black hole at the center of a galaxy, and that galaxy is moving through the universe, and sometimes that motion is a fixed velocity, and sometimes acceleration is involved, and …
What, then, is motion? And what does it mean to be stationary? What is your “point of view?â€Â What is meant by “frame of reference?â€Â Ask yourself, “Is this what is meant by relativity?â€
