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FARMS and Physics
I recently highlighted several essays in the FARMS publication, Astronomy, Papyrus, and Covenant. I want to return, briefly, to the chapter, "'And I Saw the Stars': The Book of Abraham and Ancient Geocentric Astronomy," by John Gee, William J. Hamblin, Daniel C. Peterson.
The essay argues that the Book of Abraham is presented from a geocentric point of view. In answer to the question of why God would teach Abraham using a "false" conception, the authors suggest that (i) God teaches according to our human limits of understanding, and (ii):the geocentric view of the cosmos is not, strictly speaking, false. If modern relativistic physics has taught us anything, it is that there is no absolute space, and thus no privileged point for observation of the cosmos except as has been established by convention. The geocentric system was abandoned, in the last analysis, not because it was incorrect but because, as it had developed with its cycles and epicycles, it was too complex and cumbersome. ...it would still be possible today, in light of modern relativistic physics—and if we were willing to subject ourselves to the difficulty of doing so—to construct a description of the universe that assumes the earth to be at the center.
As currently indicated on the sidebar, I am reading Timothy Ferris's Coming of Age in the Milky Way, and he made a point that I had not thought of before, and if I understand correctly, means that the quote above is incorrect (aside from the historical reason for rejecting geocentrism).
(Note: you physicists and astronomers out there--tell me if I've got this right or not.)
From a geocentric point of view, the farther away the stars are, the faster they have to move in order to circle the earth. Astronomically speaking, you don't have to get very far (I guess a circumference of one light year) before the velocity of the stars would have to exceed the speed of light in order to circle the earth every year. This would violate a fundamental principle of relativity. So the irony here is that the authors invoke relativity to support a notion that actually contradicts relativity. Sure, we could generate such a description, but it would remain "false."
Is this right or am I missing something?
Update: Whether the issue I raise has merit or not may depend on the assumptions of the model. But I'm encouraged that at least one person has noticed the problem before. See A Critique of Geocentricity.
6 comments:
Technically what he says is right although it has absolutely nothing to do with relativity. (I suspect this is the confused notion that relativity entails everything is relative - which it doesn't)
But technically one could do what he says and simply reformulate the equations describing the solar system into a co-ordinate frame that has the earth as a stable zero point. It'd be a bit of a pain, but you'd ultimately just be calculating out the new metric and then converting ones equations. The difference in this case is that rather than converting to a coordinate frame that makes solving our equations easily we do it to one that makes it much more complex.
Now one could argue that there is an error in that while there's no special point, clearly when one examines accelerations (either the sense one looks at orbits in Newtonian mechanics or looking at the geodesics in relativity) one will quickly see that the planets orbit around a place pretty close to the center of the sun.
On the other hand the historical issue is correct. When heliocentric astronomy won the day it wasn't really because it described the phenomena better. That's due both to the low quality of measurements compared to today but also because one can always adjust the geocentric/Aristotilean view by adding extra circles to the orbits. Add enough and you end up with the exact orbits of the bodies - even with modern measurements.
And to be fair if one is using Newton/Kepler the orbits don't follow those equations either. They are slightly off due to the interactions of all the various bodies on each other. The effects are small but noticeable. It's easy to deal with via computers but you can't solve the equations exactly. (The old three body problem) In a way when we use computers we're doing what the Renaissance geo-centric astronomers do.
To the ultimate question though, there really isn't a priviledged place, however we can treat acceleration/gravity as special in both Newton and Relativity. So while there isn't a privileged place there clearly are observable differences between heliocentric and geocentric astronomy. So while technical correct in a limited sense, it's false in the obvious one. (i.e. the earth moves fairly close to an ellipse with the sun at one of the foci - albeit not quite at the center of the sun)
It's interesting John would put that in since we discussed this back when we were roommates way back in the mid-90's.
Just to be clear, am I correct in understanding that the "he" in "Technically what he says is right" is the FARMS author?
What about the Ferris rebuttal? Who said anything about stars circling the earth every year?
Clark,
I think I'm with you if you are restricting the discussion to the solar system. But what about deeper space? Wouldn't you have the problem I brought up in the post regarding the velocity of stars?
LL,
I brought up the stars circling the earth, because it is a consequence, as I understand it, of putting the earth in the center of the universe. Look up at the sky at the same time every night and you will see a gradual progression of the stars across the sky (except those above the poles), that will continue through the year until they reach the original viewing point. So some constellations are only visible during certain seasons.
If the earth isn't moving, then the stars must be---very fast.
In my reading of Abraham 3, I do not necessarily get the impression that the earth is implied to be the center of the universe. I don't even necessarily get the impression that Kolob is implied to be the center. Everything is described in perspective to the earth, because that is Abraham's point of observation.
Moreover, it seems to be implied that different planets and stars can be of different orders, which orders would not be considered in the discussion of the relationship between Kolob and the earth. Yet they still exist and can be observed.
And what does it mean when it says Kolob is "nigh unto the throne of God"? Does this necessarily imply a physical relationship? When I kneel to pray, I am drawing nigh unto the throne of God, and yet my physical proximity to God has not changed.
Perhaps we read Abraham 3 too literally, or perhaps we fill in the blanks in the scriptural record with human assumptions that Abraham never intended. Perhaps a purely scientific approach to Abraham 3 will never yield satisfactory results.
I'm not sure that a geocentric model must demand that the earth remain perfectly still (ie, not rotate). You could have a rotating earth, with all the solar system objects orbiting the earth, with the background stars remaining fixed, only moving because of the earth's spin.
As for the Earth's place in the universe, you can defensibly say that it is at the center, but only in the sense that there really is no center of the universe and so any point in the universe can claim that distinction equally well. That is one of the consequences of the big bang, which was not an explosion of matter into already existing space like any normal explosion, but an explosion and expansion of space itself- so the big bang happened everywhere, which means there is no center.
Nick, while you're right, Gee and company were comparing Abr 3 to ancient models of geocentricity where the earth doesn't move like that. While the paragraph in question is a tad problematic I think their ultimate point is quite well made.
Jared, move to deeper space and you have the rotation of galaxies so stars still have movement like that. Now if you talk about inflation and the expansion of the universe where stars appear to be moving away from you then you'd have a point. But relative to the motions we normally think of we can show the foci of orbits.
"Reach Upward" while that's true to a point, the analogy of Abr 3 seems to imply that as one moves through the "shells" of the heavens the rotational periods slow. In Jewish/Christian conceptions this would lead to the shell that contained the fixed stars past which was God. So one would move to the seventh heaven and through that to an eighth area. Interestingly I'd note parallels here between Jewish heavenly ascents of this sort and the Book of Revelation. ("He who has ears to hear let him hear")
Anyway, the point being that the analogy doesn't work if we're just talking about a kind of perspectivism rather than an actual theory of the heavens. (IMO) I think Gee is right and Abraham is being taught in terms of the cultural conceptions that make it intelligible.
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