Earth is the Center of the Solar System

[Or I should say, Terran System]

I just read in today's newspaper the results of a study which concluded that as many as one out of five Americans believe that the Sun revolves around the Earth! The idea was to point out how ignorant Americans have become about very basic facts of science, but I have a bone to pick about this specific example.

One of the objectives of science is, given accurate and comprehensive data from observations, to derive the simplest and most viable interpretations of natural phenomena, often explained in terms of models and equations. This certainly holds true with the field of astronomy. And with the model of our Solar System that we universally accept as absolutely authoritative today. With our Copernican model, the Sun lies at the center of the Solar System, with the planets revolving around it in close-to-circular elliptical orbits. Earth is the third planet from the Sun. But this is not intuitively obvious from the point of view of the Earth itself. In fact, there is a more obvious interpretation that could have led to a vastly different model of the Solar System, but which would have fit with observed data as much as our model today does.

First of all, let me say that when I jump up in the air, the gravity from the Earth’s mass pulls me back down to it. But I would be equally correct in saying that the gravity from my mass pulls the Earth up to me! This is important, considering that our Sun is, far and away, the most massive object in the Solar System. It would naturally derive from this that everything else revolved around it. And this is why we accept as convention the model putting it at the center. But we can make a factually-accurate model of the Solar System with the Earth as its center!

To achieve this model, it must be accepted that all of the celestial objects of the Solar System, except for the Earth and its Moon, revolve around the Sun. But these objects, which include the planets, asteroids, and comets, do indirectly revolve around the Earth, since the Sun does (according to this Earth-centered model). The Sun, however, takes the orbital distance and position that Earth would take in the Copernican model.

The data would fit well with this Earth-centered model, and it is more intuitively obvious from an observer on Earth. But is it the simplest model scientifically? No, especially from an “objective” vantage point, far away from the Solar System. But sometimes we get carried away with notions of absolutes in science and some of these need to be countered.

Why make this point anyway? I suppose it’s just that the Earth-centered Solar System is considered to be subjectively-derived, while the Sun-centered Solar System is considered to be objectively-derived. But even with this, it’s all about from where one wishes to observe the Solar System. If an observer were looking directly down at the Sun from a point on a line lying perpendicular to the Solar System’s plane, then the Copernican model would be evident. But suppose that the same observer shifted position to be directly above the Earth. Then the Earth-centered model would be indicated, instead. It’s all about where one chooses to establish a point of reference. Terra is another name for Earth, so an Earth-centered system could be called the Terran System. But for convention’s sake, I’ll stick to the Sun-centered Copernican model, like everyone else. But beware of confusing conventions with absolutes! A model is just that: only a model. It is an abstraction designed to emphasize certain things over others, usually to illustrate a particular principle. And it has no intrinsic scientific value beyond that.