I got into a discussion with someone who earnestly and honestly believes that the sun revolves around the earth (yes, folks, they’re out there).
When I asked him how he could believe such a thing despite all the evidence that is available to the contrary, he gave me an answer which, down to the core of me I know is wrong, but I have trouble with spatial conceptualization, and so, can’t quite wrap my head around how it is wrong.
His answer was that because of relativity, it was just as equally valid to state that the sun was going around the earth as vice-versa. Since one can view the earth-sun system with either body “at rest” relative to the other, either view is perfectly plausable, he maintained.
Now, I know that that is wrong. I can take a piece of paper, put a dot in the center of it (to represent the sun) and draw an “orbit” around it. My pen moves along the orbit around and around the dot. But when I try to stop my pen, I can’t figure out how the earth should continue to appear to revolve around the sun.
I figure that the answer lies in one of two things: (1) My disputant has the wrong idea of relativity or (2) I’m lousy at spatial puzzles. My guess is #2, but I wouldn’t be surprised if it were a bit of each.
I did throw my disputant a bone, however. I told him that, in fact, the earth and the sun do, in fact, revolve around each other (in a sense). I am aware that the sun and earth actually revolve around the center of the earth-sun system (ignoring, for the moment, the gravitational effects of the other planets on the sun), which is actually not too far from the center of the sun.
So, please help me out here. It really bothers me that this kind of ignorance is running around out there and it bothers me even more that I can’t seem to grasp this simple idea.