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DanielLC comments on Open Thread, Apr. 13 - Apr. 19, 2015 - Less Wrong Discussion

4 Post author: Gondolinian 13 April 2015 12:19AM

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Comment author: Eitan_Zohar 14 April 2015 03:51:38AM *  1 point [-]

I discovered, today, a letter by the Lubavitcher Rebbe in which he claims that the sun revolves around the Earth:

One of the conclusions of the theory of relativity is that when there are two systems, or planets, in motion relative to each other—such as the sun and earth in our case—either view, namely, the sun rotating around the earth, or the earth rotating around the sun, has equal validity. Thus, if there are phenomena that cannot be adequately explained on the basis of one of these views, such difficulties have their counterpart also if the opposite view is accepted.

Secondly, the scientific conclusion that both views have equal validity is the result not of any inadequacy of available scientific data, or of technological development (measuring instruments, etc.), in which case it could be expected that further scientific and technological advancement might clear up the matter eventually and decide in favor of one or the other view. On the contrary, the conclusion of contemporary science is that regardless of any future scientific advancement, the question as to which is our planetary center, the sun or the earth, must forever remain unresolved, since both views will always have the same scientific validity, as stated.

Does anyone understand what this is trying to argue? I suspect he's saying something analogous to, you know, the universe shifting around the Earth in sync with the sun, which technically makes the sun revolve around the Earth (in a semantical sense). But I'm not confident of that.

Comment author: DanielLC 14 April 2015 08:19:39PM *  1 point [-]

Under special relativity, the laws of physics are conserved under translation and Lorentz transformations. There is no privileged position, orientation, or velocity. You could argue that we can't prove that there isn't a specific reference frame that's fundamentally true and that it doesn't just happen to be a specific one you think is cool, but that's almost certainly false.

Under general relativity, the laws of physics are conserved under continuously differentiable functions so long as the spacetime metric is altered accordingly. You can't stick cartesian coordinates in space in a sensible way no matter what, so there's no niceness to preserve. You could pick a reference frame (or whatever they call the general relativity version) where the Earth is in the center and not rotating, and you can't prove that that reference frame isn't fundamental. If you built a computer model of the universe, you could set that as the reference frame and you wouldn't need to add code to make sure it works like you'd have to with special relativity. But even if there really is some fundamentally true point of reference, which isn't necessarily true, it's not going to happen to be that one.