Geocentrism: Was Galileo Wrong?
Was the Copernican revolution a mistake? Do the stars orbit the earth once a day rather than the earth turning on its axis? Does the sun really revolve around the earth instead of the earth around the sun? Some Christians in the young earth creationist camp think so, in spite of serious scientific problems. Their view is called geocentrism. Scientists have considered the view such a dead issue that its refutation has not generally been taught in science courses for over a century. But these geocentrists claim that since the Bible talks about the sun rising and the earth standing still, we should take these statements in their simplest meaning in spite of science, and believe that the earth is at the center of the universe.
Some twenty-five years ago I was astonished to come across a tract advocating this position (van der Kamp, 1967). A colleague later learned of a conference in favor of the view, and presented a paper showing its scientific problems (Bloom, 1978). He was only able to get his paper accepted for the conference by giving it an ambiguous title and abstract. It is hard to say how prevalent this view is. Tom McIver, in his bibliography of over 1850 works entitled Anti-Evolution (McIver, 1988), lists five recent works advocating geocentrism (see our bibliography). There is also a Tychonian Society which publishes a journal in favor of the view. And a paper promoting geocentrism was recently presented at the Eastern regional meeting of the Evangelical Theological Society (Cohen, 1993).
In view of this activity, and clear evidence that few Christians know how to respond to it, we offer the following information.
There have been two main varieties of geocentrism that have been offered in the past two thousand years. They are usually labelled the Ptolemaic and Tychonian views, for their chief proponents, the ancient astronomer Ptolemy (died about AD 150) and the early modern astronomer Tycho Brahe (died 1601). Both agreed that the earth neither moves through space nor rotates on its axis, and that it is in the center of the universe, but they disagreed on whether the planets rotate around the earth or the sun. Some modern geocentrists, however, apparently admit the earth rotates but not that it moves through space. We will therefore organize our discussion under two headings: ``Does the earth rotate?'' (on its axis) and ``Does the earth move around the sun?''
The most common ancient scheme for the relation of the earth, sun, moon, planets and stars was perfected by Ptolemy of Alexandria. Eudoxus, Plato, and Aristotle had developed earlier versions of the same model. The earth was viewed as fixed and unmovable at the center of the universe. Around the earth moved the moon in the lowest orbit, then the planets Venus and Mercury, then the sun, then the outer planets Mars, Jupiter and Saturn (Uranus, Neptune and Pluto had not been discovered), and finally the stars. Since the earth itself was viewed as unmoving, all of these objects were thought to rotate around the earth westward once a day. In addition, the objects other than the sun had additional particular movements assigned to fit their observed behavior in the sky; the moon, for example, moved eastward in such a way as to make one trip around the earth eastward per month.
Does the Earth Rotate?
In Ptolemaic geocentrism, the earth does not rotate on its axis, and the difference between day and night is produced by the sun rotating around the earth. Thus any scientific evidence that the earth is rotating shows that the view is wrong.
Since the invention of radar, and the development of powerful radar transmitters that can bounce radar signals off the moon and nearby planets, it is obvious that the planets are not moving fast enough relative to the earth to make it around the earth in one day. For instance, by timing the delay for the return of the radar signal (among several methods) we can show that Mars is never closer to the earth than about 30 million miles, and that it is sometimes four times further than this. Yet to make it around the earth once a day if it were only 30 million miles away would require it to travel over 180 million miles per day, nearly 8 million miles per hour, or over 2,000 miles per second. Yet the relative motion of Earth and Mars can be measured by radar just as police measure the speed of a car, and we find that it is more like 10 miles per second, twenty times too small to cover the distance in the time available. This is, in fact, just the sort of speed we would expect if the earth is rotating on its axis rather than Mars rotating around the earth.
But nearly a century before radar was developed, a Frenchman named Foucault (pronounced ``Foo-coh'') had shown that the path of an earthbound pendulum swinging back and forth appears to rotate, because the earth is rotating under it. If the pendulum were located at the north or south pole, the pendulum's arc would rotate in a full circle westward once a day. At other latitudes, the shift is slower, due to complications introduced by the cord of the pendulum hanging at an angle to the earth's axis rather than parallel (Rockett, 1983).
Another evidence of the earth's rotation known long before the invention of radar is the so-called Coriolus effect in weather. Air blowing away from a high pressure system turns to the right in the northern hemisphere and to the left in the southern hemisphere. Air drawn into a low pressure system rotates counterclockwise in the north, clockwise in the south. A stationary earth would not produce this effect, but it can be simulated on a carousel by throwing balls back and forth between riders. If the carousel is rotating counterclockwise (as is usual), the center of the carousel is like the north pole, and the edge like the equator. A ball thrown outward will turn to the right as viewed by a rider on the carousel. A ball thrown inward, forward or backward will also turn to the right (Strahler and Strahler, 1973, p. 89; Flohn, 1969, pp. 92-97).
Thus there is strong scientific evidence that the earth is rotating once a day on its axis.
Does the Earth Move Around the Sun?
Tycho Brahe was familiar with some of the problems that had arisen by his day for the Ptolemaic form of geocentrism, though not the ones we mentioned above. He knew that Venus and Mars are sometimes much closer to us and sometimes further. That Venus showed phases like the moon and passed on the opposite side of the sun when it was further away and on this side when it was closer. As a result, he pictured a system in which all the planets rotated around the sun instead of the earth. But the earth was not viewed as a planet, and he still had the sun (and moon) rotate around the earth, and the earth itself did not rotate but was stationary.
Recent geocentrists have sometimes granted that the evidence we gave in the previous section indicates the earth rotates on its axis, but they still maintain that the earth is fixed in space. How do we respond to this claim?
The easiest-to-understand problem for this form of geocentrism relates to meteors. If we are not amateur stargazers or aren't often outside at night in rural areas, we may never have seen a meteor or ``shooting star.'' But amateur astronomers are often outside at night in dark areas and intentionally looking into the sky. It is well known among them that one sees far more meteors after midnight than before midnight. The reason for this is that (viewed looking down from above the north pole) the earth is moving counterclockwise around the sun and turning counterclockwise on its axis, so that from noon to midnight we are on the backside of the earth as it travels around the sun, and from midnight to noon we are on the front side. On the front side, the earth is hit by meteors coming toward it and may even overtake a few. On the back side, the meteors will not hit the earth unless they are travelling fast enough to catch up with it (Pasachoff, 1989, p. 555; Fredrick and Baker, 1981, p. 217; Smith and Jacobs, 1973, pp. 102, 104). For the same reason, we have lots of bugs splatter on the windshields of our cars, but very few on the rear windows! The earth is moving through space.
When Isaac Newton proposed that the same force which causes an apple to fall from a tree also holds the moon in orbit around the earth and the earth in orbit around the sun, he provided a mechanism for the motion of the planets (not to mention the stars and galaxies). Newton's law of gravity, though somewhat refined by Einstein in our century, makes it possible for us to send space vehicles out into orbit, not only around the earth, but also around the sun, and to calculate the positions of these spaceships with great accuracy, a feat impossible with any kind of theory based on geocentrism. And Newton's laws of motion show that the motion of the earth around the sun is really the motion of both around their common center of gravity, which is nearly at the same place as the sun's center. The earth is certainly not the center of the sun's motion!
Geocentrists will sometimes argue that Einstein's theory of relativity means that any reference frame is as good as any other, since all are equivalent. Therefore, their earth-centered reference frame is just as good as a sun-centered one, and science cannot distinguish between them. Unfortunately, otherwise competent scientists have sometimes said the same thing. But this is not true, as we have already shown above. Besides, Einstein's principle of relativity refers to frames of reference which are moving at a constant velocity in a straight line relative to one another (Goodman, 1983). This is not the case with the sun and earth, where the relative motion is approximately circular.
Though we cannot bounce radar off of stars, we can tell something about their motion relative to us by two means. For closer stars we can detect their sideways motion against the background of more distant stars. For stars close or far, we can detect their motion towards or away from us by a shift in the frequency of the light they emit, the so-called Doppler shift. We find in each of these motions two components, one due to the motion of the earth around the sun (which varies with a year-long period) and another due to the relative motion of the sun and the particular star (which has no such periodicity) (Pasachoff, 1989, p. 105; Fredrick and Baker, 1981, pp. 281-83). Again, clear evidence that the earth is moving around the sun.
These motions of other stars in our galaxy relative to our sun are consistent with the idea that our sun and these stars are all rotating around the center of our Milky Way galaxy. Doppler shift measurements of other galaxies such as the Magellanic Clouds or the Andromeda Galaxy show that their stars are also rotating around the centers of these galaxies (Fredrick and Baker, 1981, pp. 407-09, 440).
Finally, the discovery of the cosmic background radiation in the 1960s provides evidence for the resultant movement of the earth-sun system in the universe as a whole. Recent observations by the COBE satellite show that the temperature of the radiation is slightly higher in one direction and the same amount lower in the opposite direction, a Doppler shift indicating we are moving toward the warmer temperature and away from the cooler (Science News, 21 Apr 90, p. 245; Astronomy, Apr 90, p. 10; June 90, p. 22). The speed can be calculated at over 300 miles per second (Burstein and Manly, 1993, p. 41).
Geocentrism and the Bible:
These evidences indicate that there is no validity to the idea that the earth is the physical center of the universe. We as Christians have good reason to believe that the earth has a central place in God's redemptive plan, but it does not follow from this that our location is central. God warned the nation of Israel not to think that because He had chosen them they were particularly great in themselves. The situation here is similar.
But what about those passages in Scripture which seem to indicate that the earth is standing still? The strongest passages of this sort are those that speak of the sun rising, or the sun and moon standing still at Joshua's command. None of these provide any support for the recent form of geocentrism in which the earth rotates but does not move through space. All of these passages are being misinterpreted when we read them to mean that the earth cannot be going around the sun. The Bible writers are speaking from a reference frame located at some point on the surface of the earth, and this is exactly the case with modern astronomers when they speak of the time of sunrise at Philadelphia. We no more need to fear that the One who inspired Scripture is making a mistake in the one case than are the astronomers in the other.
Robert C. Newman, PhD, astrophysics
Biblical Theological Seminary
McIver, T. 1988. Anti-Evolution: An Annotated Bibliography. McFarland. Jefferson, North Carolina and London.
Works on Science Not in Favor of Geocentrism:
Bloom, J. A. 1978. ``Geocentricity: What saith the Scriptures?'' Address at the Biblical Cosmology and Geocentricity Conference, June 5-7, 1978, Cleveland State University, Cleveland, OH (sponsored by the Tychonean Society).
Burstein, David and Peter L. Manly. 1993. ``Cosmic Tug of War'' in Astronomy 21, no. 7 (July, 1993): 40-45.
Flohn, H. 1969. Climate and Weather. McGraw-Hill World University Library. New York.
Fredrick, L. W. and R. H. Baker. 1981. An Introduction to Astronomy. 9th ed. Van Nostrand. New York.
Goodman, B. 1983. ``Frame of reference'' in McGraw-Hill Encyclopedia of Physics. McGraw-Hill. New York.
Pasachoff, J. M. 1989. Contemporary Astronomy. 4th ed. Saunders. New York.
Rockett, F. H. 1983. ``Foucault pendulum'' in McGraw-Hill Encyclopedia of Physics. McGraw-Hill. New York.
Smith, E. v. P. and K. C. Jacobs. 1973. Introductory Astronomy and Astrophysics. W. B. Saunders. Philadelphia.
Strahler, A. N. and A. H. Strahler. 1973. Environmental Geoscience. Hamilton Publishing. Santa Barbara, California.
Works in Favor of Geocentrism:
Bouw, Geerhardus. 1984. With Every Wind of Doctrine: Biblical, Historical and Scientific Perspectives on Geocentricity. Tychonian Society. Cleveland.
Cohen, Merrill A. 1993. ``Heliocentrism vs. Geocentrism: Defiance or Defense of the Gospel?'' Paper presented at the Eastern Regional meeting of the Evangelical Theological Society, April 2, 1993.
Elmendorf, R. G. 1978. How to Scientifically Trap, Test and Falsify Evolution. Bible-Science Association of Western Pennsylvania. Bairdford, Pennsylvania.
Hall, Marshall and Sandra Hall. 1977. The Connection Between Evolution Theory and the Going Together of the True Church. P/R. Lakeland, Florida.
Hanson, James. 1979. A New Interest in Geocentricity. Bible-Science Association. Minneapolis.
Hills, Edward F. 1979. Space Age Science. 2nd ed. Creation Research Press. Des Moines, Iowa.
Ptolemy, Claudius. c150 AD. Great Synthesis or Almagest.
Tycho. 1602-03. Astronomiae Instauratae Progymnasmata.
van der Kamp, Walter. 1967. The Heart of the Matter. 8611 Armstrong Ave., Burnaby, B.C., Canada.