The Earth-Sun Relationship: A Matter of Perspective

[BobG]

Is this not legit:

Einstein and Infeld, The Evolution of Physics, p. 212 (248 in 1938 ed)):

"The struggle, so violent in the early days of science, between the views of Ptolemy and Copernicus would then be quite meaningless. Either coordinate system could be used with equal justification. The two sentences, 'the sun is at rest and the Earth moves,' or 'the sun moves and the Earth is at rest,' would simply mean two different conventions concerning two different coordinate systems." Major figures in cosmology, physics, and astronomy (Albert Einstein, Max Born, Stephen Hawking, George Ellis, and Fred Hoyle, among others) are in agreement that there is no scientific way to prove either model over the other, nor any non-philosophical/theological justification for doing so, SPECIFICALLY in the context of General Relativity.

You can make the bookkeeping work out in any reference frame you want, so I'd say it's impossible to prove mathematically which model is correct. And the laws of physics apply regardless of the reference frame you're in.

I don't think that should be confused with what's actually happening.

Instead, that's a reason you need some actual observations of what's happening instead of 'proving' a model solely with mathematics (although the laws of physics and mathematics could certainly prove a model can't possibly be true).

And calculations in the Copernicus model was no easier than the Ptolemaic model, since a solar system filled with circular orbits required just as many epicenters and deferents as the Ptolemaic model. You didn't get an easier model to work with until the Keplerian model with elliptical orbits.

But it is a perfect example of being unable to prove the reality of either model solely by the math, since the laws of physics worked in both. It takes some other observations such as "can you detect any change in the angles between stars as you orbit the Sun?" to prove which is correct, except if don't know how far away the stars are and have no way to measure their difference, in fact, don't even have the capability to measure really small changes in their angles (it wasn't until Galileo that telescopes even started being used for observations) you don't know if the answer to that question really proves your point or not.

Not only did people not know how far away the stars were, they didn't even know how far away the Sun was (hence the long tradition of measuring planetary distances in "astronomical units" instead of a unit of known length, such as meters). In fact, the world's first international science project was an attempt to use the transit of Venus in the 1770's to finally, once and for all, detrmine just how far away the Sun was from the Earth.

That doesn't mean both models can accurately describe reality. It just means there's no way to determine which model describes reality.

 

[jackoblacko]

That doesn't mean both models can accurately describe reality. It just means there's no way to determine which model describes reality.

Much appreciated from all. I think I might understand, and although your explanation is good I'm afraid I wouldn't without Feynmans lecture series here

By our understanding of models or representations or whatever (I don't want to be to specific in the wording) things could work any of these ways I described. The sciences basically admit that.

But that's not to say they are equal, or that one is not more useful or even plausible than the other.

The best example I just thought of would be that the model of the solar system can function backwards, but we would be hard pressed to show that it does.

Science or physics isn't interested in exploring those thoughts, but rather seeks to explain the things that help our understanding of the tangible application to reality?