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Geocentrism is the belief that the sun, the planets and all the stars revolve around the Earth. You can thank the Old Testament for the lingering belief in this one. It has at least four verses claiming that the earth "cannot be moved," and one stating that the sun goes around the earth.


[edit] History

Geocentrism was the standard model throughout the Western world during antiquity, the Middle Ages and the Renaissance.

Ptolemy's theory of the solar system placed all celestial bodies orbiting around the Earth, with epicycles introduced to compensate for the retrograde motion of planets such as Mars. The ancient Greeks noted that, if the Earth did move around the sun, the stars should appear to shift their positions from one part of the year to the next and the Ancient Greek philosophers did not observe any changes in stellar positions. Alternatively the stars would have to be so ridiculously far away that the shift in position was too small to be seen by the naked eye. Hey, that would make for a ludicrously large empty space between the most distant planet, Saturn, and the "fixed stars". (Measurements dependent on naked-eye instruments could detect a parallax of something like one arc-minute, which would give a distance more than 300 times the distance to Saturn.)

Some late medieval scholars, notably Nicholas of Cusa and Nicolas Oresme, brought up the possibility that the Earth might move, but Nicolaus Copernicus was the first to challenge the geocentric model seriously, suggesting a heliocentric universe in 1514. Copernicus's theory was promoted by Galileo Galilei, provoking hostility from the Church who denounced it as heresy. Probably due to this controversy, Copernicus's book was still listed on the Index (the list of books banned by the Catholic Church) between 1616 and 1758.

[edit] Victory of heliocentrism

It was a mixture of different reasons that led to the final "victory" of heliocentrism (symbolized by the Catholic Church's capitulation in1758). In 1551, the astronomer Erasmus Reinhold published the Prutenic Tables , astronomical tables, computed by the Copernican model, which were an improvement on tables based on Ptolemaic astronomy. In 1588, Tycho published his comprise system. Galileo's telescopic observations (announced beginning in his1610 Sidereus Nuncius|Starry Messenger) revealed a heavens different from the traditional conceptions: the phases of Venus, mountains on the Moon, satellites of Jupiter and spots on the Sun. Newton's 1687 Principia put the mechanics of the Solar System on a secure mathematical and physical basis. By 1729, it was an anticlimax when James Bradley discovered stellar aberration, measuring the orbital speed of the Earth in orbit.

[edit] For the Bible tells us so

Geocentric is suggested in several Biblical passages, depending on how these passages are interpreted. In order of appearance, the verses are:

  • Joshua 10:12-13: On the day the LORD gave the Amorites over to Israel, Joshua said to the LORD in the presence of Israel: "O sun, stand still over Gibeon, O moon, over the Valley of Aijalon." So the sun stood still, and the moon stopped, till the nation avenged itself on its enemies, as it is written in the Book of Jashar. The sun stopped in the middle of the sky and delayed going down about a full day.
  • 1 Chronicles 16:30: Fear before him, all the earth: the world also shall be stable, that it be not moved.
  • Psalm 19:6: It [the sun] rises at one end of the heavens and makes its circuit to the other; nothing is hidden from its heat.
  • Psalm 93:1: The LORD reigneth, he is clothed with majesty; the LORD is clothed with strength, wherewith he hath girded himself: the world also is established, that it cannot be moved.
  • Psalm 96:10: Say among the heathen that the LORD reigneth: the world also shall be established that it shall not be moved: he shall judge the people righteously.
  • Psalm 104:5: (Bless the LORD . . .) Who laid the foundations of the earth, that it should not be removed for ever.
  • Ecclesiastes 1:5: The sun also ariseth, and the sun goeth down, and hasteth to his place where he arose.

[edit] Modern geocentrism

In the modern world, small subset of Biblical literalists and other scientifically illiterate cranks promote some form of geocentric worldview. This can be varied. "Geocentrism", taken literally, means that the earth is at the center and that is consistent with daily rotation of the earth, without the earth orbiting the sun annually. Still this is not how geocentrism was traditionally understood, and is not how it persists today. Geocentric models claim the earth does not move at all, which means that the entire universe revolves around the earth daily. (This would mean that the stars and galaxies revolve around the Earth once every 24 hours, despite modern astronomy demonstrating that they are many light-years away and would therefore have to race round faster than light.[1]) A person can take a relativistic view, that "all motion is relative", and claim one cannot tell the difference between the earth being in motion and it being fixed. This has the drawback that the Bible does not make false statements about the fixity of the earth, but instead makes meaningless statements; and therefore it rarely comes up.

21st century believers in a fixed earth may distance themselves from the Ptolemaic system of epicycles. Some call their model geocentricity in an attempt to make that clear. They may prefer a "compromise" position first suggested by Tycho Brahe: the Sun revolves around the earth, but the planets revolve around the Sun. The Bible says nothing about the motions of the planets (and the stars), so any description of the movements of the heavenly bodies can fit the Bible, as long as the earth is fixed and the sun is in a closed path around the earth.

A minority of fairly dense fundamentalists and apathetic people believe modern geocentrism. There are more than one might assume, though, and in the United States, Great Britain and Germany between 16% and 19% of people actually believe the sun goes round the earth. [2] Some geocentrists are rather vocal, have websites, [3] and would like you to know that at least they're not as dumb as those heretical Flat Earthers.

[edit] Debunking geocentrism

The only evidence for modern geocentrism is that the Old Testament (the product of a culture which knew of no alternative to geocentrism) refers to a geocentric universe. Commentators on biblical cosmology saw no reason to think that Bible was using figurative language - until the rise of modern science.

Geocentrists will appeal to nineteenth-century experiments which tried to measure the movement of the Earth, and got a zero answer - such the Michelson-Morley experiments and Airy's water-filed telescope. However, the special theory of relativity explains these results in a heliocentric model.

[edit] Geocentrists' replies to arguments against their position

Geocentrists have some pat replies to common arguments against their position (heliocentric argument in ordinary font, geocentric replies in bold):

  • They will argue that pictures from outer space showing the Earth in motion can be explained by the relative motion from the camera, not absolute motion of Earth.
  • They will argue that phenomena that reveal the motion of the Earth, such as the Foucault pendulum and the Coriolis effect, are accounted for by appealing to something like Mach Principle, by which any consequence of rotation of the Earth is the same as would occur with the movement of the "fixed stars" around a fixed Earth.
  • Phenomena such as the phases of Venus and Mercury and the retrograde motion of Mars (and of the more distant planets) present no problem to modern geocentrism, for it typically adopts Tycho's model (in which those planets orbit the Sun).
  • Any geometric configuration of the Solar System, and thus any kinematic description of its motions, and any dynamic equations which have the Sun as the center, can equally (if not conveniently) be described with a coordinate system with the Earth as the zero point, for example in suitably chosen Lagrangian coordinates. (This is done within classical Newtonian mechanics.)
  • Objects as far away as Neptune (whose orbit has a radius of 4 light-hours) would have to move more than the speed of light to circle the the Earth in 24 hours. In response, geocentrists will deny Einstein's theory of relativity or argue that the objects are moving at a normal speed through a space that is also moving. (in General Relativity, space itself can move faster than light.)
  • We read about how a major earthquake changes the rotation of the Earth, which proves that the Earth really has a rotation. The geocentrists point out, however, that that is only a calculated estimate, and that we not have the technology to measure the small differences that are involved. Even if this correlation with earthquakes should become measurable, as long as the cause of earthquakes are not well enough known to predict earthquakes, one cannot rule out that a change in the rotation of the heavens is the cause of earthquakes, or there is a common cause for both.
  • Some Bible readers claim that the "true" meaning of the Biblical passages which are used to support geocentrism are discovered to be quite the opposite. The Hebrew is revealed to mean something else, or else the context is poetic or other metaphorical speech. To which it can be pointed out that no one, up to the time of modern science, observed that the Bible was consistent with heliocentrism, and no one suggested consistency, except under the influence of modern science. If one is going to let modern science make us change the plain meaning of Scripture, we might as well be evolutionists.

[edit] Arguments for which the geocentrists (thus far) do not have replies

[edit] Daily rotation of the Earth

The rotation of the Earth isn't completely smooth, there is a slight wobble. The planet's rotation speeds up and slows down slightly and the point its axis changes a little. [4]

  1. Heliocentrists can explain this easily: it moves.
  2. Geocentrists have to imagine that the stars and galaxies all wobble in synchrony while Earth stays still. Each wobble started at a different time so the light from these different objects reaches us at the same time making it look simultaneous. [5]

[edit] See also


[edit] External links

[edit] Footnotes

  1. Actually, the problem of faster-than-light occurs at the position of the planet Neptune.
  2. New Poll Gauges Americans' General Knowledge Levelsmodern medievalism: Geocentrism
  3. The non-moving Earth & anti-evolution web page of The Fair Education Foundation, Inc. Static Earth, Ready to have your world view shaken
  4. What is the Chandler wobble?
  5. So for a wobble detected by a telescope now:
    1. The space probe Voyager 1 is so far away that its radio signal takes about 17 hours to reach Earth. The wobble on the position of Voyager 1 (on the geocentric model) must have happened 17 hours ago.
    2. A star 10 light years away wobbled 10 years ago,
    3. Stars 100 light years away wobbled 100 years ago,
    4. Galaxies 10 billion light years away must have wobbled before the Solar system formed.
    The light from all these wobbles that actually happened at different times reaches us simultaneously giving the illusion that the whole universe wobbles synchronously. Insofar as we can identify a change on Earth related to the wobble, the distant wobbles happened before the Earth event.
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