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> One interpretation is the earth is the center of the universe, and the sun and stars move around it. Another is the sun is at the enter Then along comes rela

> One interpretation is the earth is the center of the universe, and the sun and stars move around it. Another is the sun is at the enter Then along comes relativity theory and says that both of these are equally right. There is no "center" and therefore when making calculations you should just pick whatever center - frame of reference, that is - makes the calculations simpler. For example, you'll have a much easier time doing the math of planetary motion if you pick the sun as your frame of reference, but you could pick the earth if you wanted to. However, if you want to calculate the movements of stars in the Milky Way, you should no longer use the sun as your frame of reference - instead, use the center of the galaxy.

prox 6y ago
But you could, if you wanted to? At least by your analogy?
- esperent 6y ago
  Yes, you could, in theory, although the math would probably be so complex you could never solve it. This isn't an analogy though, it's a direct consequence of relativity theory. It's the reason the word "relativity" is in the name.
antonvs 6y ago
It's true that there's no universal center, and relativity supports this. However, dropping the idea of a universal center, it's false that the Earth is the center of the solar system, i.e. the other major objects in the solar system don't revolve around the Earth, even though it's possible to produce a consistent Earth-centric model that works like that. Relativity doesn't say that both an Earth-centric and solar-barycentric models are equally correct, since the Earth-centric model is not an inertial frame, and Earth's contribution to spacetime curvature is one of the smaller ones. Both special and general relativity allow us to draw reliable conclusions about which models better represent reality, as opposed to just making accurate predictions. As such, this example provides better support for the idea that interpretations matter, than that they don't. It suggests that the situation with quantum interpretations may well be similar. You can make accurate predictions under any sufficiently complete interpretation, but that doesn't mean that there isn't an interpretation that's a better fit to reality than others. We may just lack the ability to determine that yet. Aaronson's take is similar to the "shut up and calculate" take in the sense that it explicitly ignores or rejects the question here. It's an anti-knowledge position - it's saying we should be happy with what we already know, and simply work within that framework, ignoring deeper questions. It's the position of an engineer rather than a fundamental research scientist.
- esperent 6y ago
  > Relativity doesn't say that both an Earth-centric and solar-barycentric models are equally correct I'm fairly sure it does. Of course, you'll get the same answer either way - the earth moves in an elliptical orbit around the sun and contributes a tiny amount of the total inertia of the system. But you can use either the sun or the earth as your frame of reference to calculate this. It's explained quite well on wikipedia so I'll just quote that here: > Albert Einstein and Leopold Infeld wrote in The Evolution of Physics (1938): "Can we formulate physical laws so that they are valid for all CS (=coordinate systems), not only those moving uniformly, but also those moving quite arbitrarily, relative to each other? If this can be done, our difficulties will be over. We shall then be able to apply the laws of nature to any CS. The struggle, so violent in the early days of science, between the views of Ptolemy and Copernicus would then be quite meaningless. Either CS 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 CS. Could we build a real relativistic physics valid in all CS; a physics in which there would be no place for absolute, but only for relative, motion? This is indeed possible!"[47] > Despite giving more respectability to the geocentric view than Newtonian physics does,[48] relativity is not geocentric. Rather, relativity states that the Sun, the Earth, the Moon, Jupiter, or any other point for that matter could be chosen as a center of the Solar System with equal validity. > Relativity agrees with Newtonian predictions that regardless of whether the Sun or the Earth are chosen arbitrarily as the center of the coordinate system describing the Solar System, the paths of the planets form (roughly) ellipses with respect to the Sun, not the Earth. With respect to the average reference frame of the fixed stars, the planets do indeed move around the Sun, which due to its much larger mass, moves far less than its own diameter and the gravity of which is dominant in determining the orbits of the planets (in other words, the center of mass of the Solar System is near the center of the Sun). The Earth and Moon are much closer to being a binary planet; the center of mass around which they both rotate is still inside the Earth, but is about 4,624 km (2,873 mi) or 72.6% of the Earth's radius away from the centre of the Earth (thus closer to the surface than the center).[citation needed] > What the principle of relativity points out is that correct mathematical calculations can be made regardless of the reference frame chosen, and these will all agree with each other as to the predictions of actual motions of bodies with respect to each other. It is not necessary to choose the object in the Solar System with the largest gravitational field as the center of the coordinate system in order to predict the motions of planetary bodies, though doing so may make calculations easier to perform or interpret. A geocentric coordinate system can be more convenient when dealing only with bodies mostly influenced by the gravity of the Earth (such as artificial satellites and the Moon), or when calculating what the sky will look like when viewed from Earth (as opposed to an imaginary observer looking down on the entire Solar System, where a different coordinate system might be more convenient https://en.m.wikipedia.org/wiki/Geocentric_model#relativity https://en.m.wikipedia.org/wiki/Geocentric_model#relativity See in particular this sentence: > It is not necessary to choose the object in the Solar System with the largest gravitational field as the center of the coordinate system in order to predict the motions of planetary bodies, though doing so may make calculations easier to perform or interpret. That's exactly the point I made above.

prox 6y ago

But you could, if you wanted to? At least by your analogy?

esperent 6y ago
Yes, you could, in theory, although the math would probably be so complex you could never solve it. This isn't an analogy though, it's a direct consequence of relativity theory. It's the reason the word "relativity" is in the name.

antonvs 6y ago

It's true that there's no universal center, and relativity supports this. However, dropping the idea of a universal center, it's false that the Earth is the center of the solar system, i.e. the other major objects in the solar system don't revolve around the Earth, even though it's possible to produce a consistent Earth-centric model that works like that. Relativity doesn't say that both an Earth-centric and solar-barycentric models are equally correct, since the Earth-centric model is not an inertial frame, and Earth's contribution to spacetime curvature is one of the smaller ones. Both special and general relativity allow us to draw reliable conclusions about which models better represent reality, as opposed to just making accurate predictions. As such, this example provides better support for the idea that interpretations matter, than that they don't. It suggests that the situation with quantum interpretations may well be similar. You can make accurate predictions under any sufficiently complete interpretation, but that doesn't mean that there isn't an interpretation that's a better fit to reality than others. We may just lack the ability to determine that yet. Aaronson's take is similar to the "shut up and calculate" take in the sense that it explicitly ignores or rejects the question here. It's an anti-knowledge position - it's saying we should be happy with what we already know, and simply work within that framework, ignoring deeper questions. It's the position of an engineer rather than a fundamental research scientist.

esperent 6y ago
> Relativity doesn't say that both an Earth-centric and solar-barycentric models are equally correct I'm fairly sure it does. Of course, you'll get the same answer either way - the earth moves in an elliptical orbit around the sun and contributes a tiny amount of the total inertia of the system. But you can use either the sun or the earth as your frame of reference to calculate this. It's explained quite well on wikipedia so I'll just quote that here: > Albert Einstein and Leopold Infeld wrote in The Evolution of Physics (1938): "Can we formulate physical laws so that they are valid for all CS (=coordinate systems), not only those moving uniformly, but also those moving quite arbitrarily, relative to each other? If this can be done, our difficulties will be over. We shall then be able to apply the laws of nature to any CS. The struggle, so violent in the early days of science, between the views of Ptolemy and Copernicus would then be quite meaningless. Either CS 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 CS. Could we build a real relativistic physics valid in all CS; a physics in which there would be no place for absolute, but only for relative, motion? This is indeed possible!"[47] > Despite giving more respectability to the geocentric view than Newtonian physics does,[48] relativity is not geocentric. Rather, relativity states that the Sun, the Earth, the Moon, Jupiter, or any other point for that matter could be chosen as a center of the Solar System with equal validity. > Relativity agrees with Newtonian predictions that regardless of whether the Sun or the Earth are chosen arbitrarily as the center of the coordinate system describing the Solar System, the paths of the planets form (roughly) ellipses with respect to the Sun, not the Earth. With respect to the average reference frame of the fixed stars, the planets do indeed move around the Sun, which due to its much larger mass, moves far less than its own diameter and the gravity of which is dominant in determining the orbits of the planets (in other words, the center of mass of the Solar System is near the center of the Sun). The Earth and Moon are much closer to being a binary planet; the center of mass around which they both rotate is still inside the Earth, but is about 4,624 km (2,873 mi) or 72.6% of the Earth's radius away from the centre of the Earth (thus closer to the surface than the center).[citation needed] > What the principle of relativity points out is that correct mathematical calculations can be made regardless of the reference frame chosen, and these will all agree with each other as to the predictions of actual motions of bodies with respect to each other. It is not necessary to choose the object in the Solar System with the largest gravitational field as the center of the coordinate system in order to predict the motions of planetary bodies, though doing so may make calculations easier to perform or interpret. A geocentric coordinate system can be more convenient when dealing only with bodies mostly influenced by the gravity of the Earth (such as artificial satellites and the Moon), or when calculating what the sky will look like when viewed from Earth (as opposed to an imaginary observer looking down on the entire Solar System, where a different coordinate system might be more convenient https://en.m.wikipedia.org/wiki/Geocentric_model#relativity https://en.m.wikipedia.org/wiki/Geocentric_model#relativity See in particular this sentence: > It is not necessary to choose the object in the Solar System with the largest gravitational field as the center of the coordinate system in order to predict the motions of planetary bodies, though doing so may make calculations easier to perform or interpret. That's exactly the point I made above.