THIRD BRIEF: A reference point (a point held fixed) can be placed anywhere.

Back to my favorite motto from the Science Channel: “Question Everything”

If you ask anyone, “Does the sun revolve about the earth, or does the earth revolve about the sun?” the answer is obvious. Any grade school kid knows that the earth revolves about the sun. Nicolaus Copernicus resolved that conundrum back in the 1500’s by identifying the heliocentric solar system with the sun at the center. No argument here, right?

Not so fast. Think about this: from here on the surface of the earth, every 24 hours we observe the sun come up in the morning, travel across the sky, go down in the evening and then come back up again the next morning.

Is that an illusion?

Relative to you and me the sun circles about the earth every 24 hours. That’s no illusion. We see it happen every day. This is called “empirical proof.”

Actually the correct answer depends on where you put the reference point. When referring to "relative motion" with respect to a reference point, scientifically there is nothing that says one reference point takes precedence over another. Thus, if we put the reference point at the sun, the earth circles about the sun every 365 days. If we put the reference point at the earth (where we are), the sun circles about the earth every 24 hours. In fact both are happening coincidentally.

So in reality, all Copernicus did was move the reference point from the earth to the sun.

No offence to Copernicus.  After all, back in his time that was a pretty remarkable thing to do.

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