Comment by its_ethan
3 hours ago
I mean to be completely accurate the Earth doesn't strictly orbit the Sun. Both the Sun and Earth orbit each other around a point at their "combined" center of mass, the barycenter - https://en.wikipedia.org/wiki/Barycenter_(astronomy). This is something you need to take into account for all the planets in the solar system and as a result, the "center" of the whole system is constantly moving. The solar system's barycenter is often not even inside the Sun.
I think that sort of proves the point that the OP was making, which is that you can create a functional model around any arbitrary location and it can be valid (as long as valid means: it can make useful predictions). When you put the center of the Sun at the center of the model, you still need your models to account for the "orbital wobble" happening as a result of the Sun doing a little dance with Jupiter (and all the other masses that orbit it) in the equations for the determining the relative positions of the Sun and Earth.
Using the Sun as the center versus the solar systems barycenter are both somewhat "arbitrary" in that way, and depend on what you're trying to do with the information - how accurate you need it to be, and how complicated you're willing to make the calculations to hit higher accuracies.
If I just add a few more parameters to my model I can make it fit anything!
Sure, it depends on what you're trying to do. Fit an equation or understand it. Yes, you can use a reduced mass to simplify the equations and make it more accurate, which usually isn't necessary when the new center is at less than 1% of the radius of the Sun (note ellipses have 2 foci from Kepler/Newton). Even Jupiter's center of rotation is at the surface of the Sun, and both have eccentricities <1%.
Of course, if you're using epicycles, you're never going to get Einstein's elliptical precession correction to the orbit of Mercury. Simpler, is usually better for models, even when you need greater and greater accuracy, overfitting is the enemy of explanation (to coin a phrase).
All models are wrong, some are useful. - Box
> If I just add a few more parameters to my model I can make it fit anything!
Dealing with people wanting to do this is story of my current professional life lol I would love to get them onto the same page that chasing down a final <1% improvement isn't (always) worth it
"All models are wrong, some are useful" - this is what I was trying to say, I was just being a bit snarky/pedantic because the commenter above seemed to be trying to pull a "gotcha" saying that the "truth" of something overrides the utility of it.
Agreed. So to return to the root comment... if AI can generate for us all of those "wrong" models in a consistent way, then the job that remains for humans is to decide which one or ones would be useful. I bet it turns out to be a lot more work than it sounds like.