The Earth Revolves Around the Sun

//The problem, however, is that the bulk of our understanding of gravity and of the related centripetal acceleration comes from our observations of planetary movements. You are therefore arguing that: //We derive G from observing M. Therefore G explains M. //That is circular and self-fulfilling reasoning. And applying scientific definitions to the application of this reasoning only conceals the basic fallacies of the underlying logic. False. We understand how centripetal acceleration works separate from planetary motion. Centripetal acceleration is simply the inward acceleration needed for an object to follow a certain path. Not only can we come to the equations we have mathematically, but they also work no matter where we apply them (car races, a guy spinning a lasso around his head, etc.). However, I did largely bring up the other planets and their respective orbits around the sun as evidence of our current theories of gravity being correct. This is because the movement is planetary bodies is governed almost exclusively by gravity. While no other applications are problematic for gravity either, there are other forces at work, and I like to keep it simple. Or at least as simple as possible. Irregardless, using the relative movements between the sun and other planets is still valid. Whether or not the sun orbits us or vice versa, we can still accurately describe the relative motions of the sun and other planets, based on the fact that we can observe both. Using this information, we could construct an orbit for each planet (or moon, etc.). These orbits would be observed data, not theoretical data based on gravitational theory, but it just so happens that gravitational theory very accurately describes the exact same orbits we observe. However, if the sun orbits us, then gravity does not explain _any_ of the orbits very well. //Nor does a lack of counter-evidence equate to a proof. We have only the circumstantial evidence that one and the other seem to explain each other. No, but an abundance of extremely accurate applications does. Gravitational theory is proven to work just about as much as any scientific theory ever will be. //If this any of this is a strawman, I'd ask you to spell out your logical argument in a simple skeletal framework and demonstrate sound argument that your position is correct. Done. In case you didn't catch it, I wasn't using gravity and centripetal acceleration to mutually prove each other, like you said I was. //Assuming, of course, that we could get so far away and continue to observe real-time movements for long enough periods of time to observe motion. From outside the solar system, where of course the SPACE SHUTTLE has not travelled, we cannot videograph the entire solar system for the very lengthy period of time it would take to adequately observe the movements. Consequently, we have only still-photographs, which is not enough to clarify the movements. Perhaps we cannot right now, but I see no reason why it isn't possible. That statement was more to show that you _can_ be disproven by direct observation of the alternative, since it seemed like you were asserting that it was impossible to ever possibly know. That might have been a straw man on my part, but it wasn't the bulk of my argument either. I'll reply to your new theory. //1) All Planets revolve around the Sun except the Earth because of the Sun's gravity. No arguments there. //2) The location of the Earth is fixed for reasons we do not yet understand. Based on relativity, there is no such thing as 'fixed' position, since being fixed in position with respect to one thing necessarily means moving with respect to some others. If you meant "The location of the earth with respect to our solar system is fixed for reasons we do not yet understand," please see my entire 3rd point from the last post. //3) The Sun's own gravity pulls it in rotation around the Earth, dragging the other planets along with it. No. As I already stated, the gravitational forces between the sun and earth are not _nearly_ strong enough to move the sun around the earth. I'll explain it clearer: The gravitational _force_ between two objects is constant. Let's say the force between earth and sun at the current distance is 1. Let's also say the mass of earth is 1 and the sun is 100 (would be much more). The earth would accelerate at 1 unit distance/time squared. The sun would accelerate at 1/100 unit distance/time squared. Now I'll explain the math of centripetal acceleration. The acceleration needed to make something make an orbit of radius r while traveling at v velocity is a = v^2/r Since the orbit being described would mathematically be the same whether A was orbiting B or B was orbiting A, the speed and radius of the orbit would be the same either way. They would also require the same acceleration, though as I just showed, the sun would have considerably less gravitational acceleration to accomplish this. It would need some new force to also pull it toward the earth, though this force would have to also not affect the other planets at all. Actually it would have to, because the planets right now take only their orbital paths. The magical force would have to also give each planetary body besides the magical earth the orbit of the sun as well. What I mean by this is that the normal, explained, observed orbit would not automatically travel with the sun as it moves, requiring at times much more or much less force between them to keep the orbits we see. If the orbit of the planet (besides earth) is A and the orbit of the sun around the earth is B, each planet would somehow need to be following path A+B. //4) Hence, the Earth might be the center of the solar system. Hence, the Earth is not the center of the solar system. Fixed. It's possible to argue any science in a similar way. By discarding accurate theories for baseless what-if's, there appears to be some chance that there are in fact leprechauns, with pots of gold, at the end of every rainbow. Such tactics do not belong in debate unless you have good reason to discard theories and something to actually base your what-if's on besides your own imagination. In any event, it's been fun.