Della:
What about gravity. Wouldn’t the center of the universe or even a solar system have to have enormous gravity to hold everything in its orbit?
Our sun is much bigger than earth and has a much stronger gravity, as does Jupiter. We are between these two huge bodies that keep us where we are in space. Isn’t that so?
If the earth were the center of the universe it would have to have tremendous gravity to hold everything in its orbit–gravity so great no living thing could possibly live on it. Aren’t I right about that?
The relationship of gravity and mass were theorized by Einstein’s general theory of relativity, which basically takes the special theory and adds gravity and acceleration.
Gravity is thought of most popularly in Newtonian terms, as an interactive force between two masses. The bigger the masses, or the closer their center-of-mass physically, the greater this “force” that acts both ways between the objects.
What we also know is that mass can be exchanged for energy, according to the famous equation E = mc^2 (or slight variations thereof) so the presence of mass and the presence of a highly concentrated field of potential energy are both valid models for the same thing. These fields actually create curvature in space, as predicted by Einstein and validated in a famous experiment during a solar eclipse. Skipping ahead a few steps, light always goes through space in a straight line so when we see light “bend” around a gravitational field (note this is NOT the same as refraction as through glass but works much the same way) such as that of our own sun in the experiement, we can either say that light went around a corner, or as Einstein found, it can be shown that the space itself was curved around that object.
When one argues that the earth is the center of the universe, one can certainly do so and one can exclude views to the contrary. The problem is there is no such thing as a common reference frame for all this. For example, if our continents are moving at several inches per year, then which point on the earth itself is considered the center? It is truly a personal point of view.
Mathematics likes to accept as “truth” whatever model is easiest or most “elegant” in some way (usually simplicity) to explain things. For example, we can explain the motion of the moon related to the sun using existing mathematics, in a way much simpler if we look at the moon as a satellite around us, but I assure you that moon pushes and pulls on us (hence the tides) every bit as much as we push and pull on it to keep it in place. The earth actually “wobbles” a bit off center because of this, but only again if you expand the point of view from earth-centric to earth-moon system-centric.
When people say that earth-centered cannot be “proven” I feel this is an extremely limited way to look at it. Certainly we have to define what we mean by “earth centered” and when we say immovable I have to ask, “by what measure” because all of these things are matters of free choice. The Church as well as individuals may say what they will and the universe behaves the same with a different story told about the mechanics with different angles of approach at explaining which leas to seemingly different observations of exactly the same phenomena.
That said, I think TheWhim is making a pretty good case that this “earth-centric” view has some specific meaning in an absolute sense, and that by not adopting it Galileo was wrong. I’m not bothered that we are focused on the fact that the Church was also “wrong” with earth-centric view.
The problem I have is I don’t see that “earth centric” is subject to an absolute answer one way or another. It is simply a way to describe things, much as an author of a book has to make decisions whether to unfold the book this way or that – for example by building each character separately or by unfolding chronilogically or whatever. Therefore the Church can define whatever she wants to as far as the point of view. Now if she goes around telling people they are stupid for holding contrary points of view, which I believe is the charge TheWhim is making, at first I’m inclined to agree.
That doesn’t mean I’m leaving the Church, though. It just means that I don’t listen to everything I am told that she says or does, and frankly, I’m not convinced that the pope is open to perfect discernment in matters of physics, but of faith. It is for this reason I can actually defend, I believe, either side of this argument.
Sorry, TheWhim, but I have not read all of the sources before posting. I’m a slow reader and I simply cannot get it all read – at least as far as I’m willing to spend time on the issue. Still, I have enjoyed the argument thus far – just when we start talking about the nature of gravity I get all excited.
Alan