Sistem Tychonik: Perbedaan antara revisi

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It is essentially a [[geocentric model]]; the [[Earth]] is at the center of the universe. The [[Sun]] and [[Moon]] and the stars revolve around the Earth, and the other five [[planet]]s revolve around the Sun. It can be shown that the motions of the planets and the Sun relative to the Earth in Brahe's system are mathematically equivalent to the motions in Copernicus' [[heliocentrism|heliocentric]] system, <ref>"The Tychonic system is, in fact, precisely equivalent mathematically to Copernicus' system." (p. 202) and "[T]he Tychonic system is transformed to the Copernican system simply by holding the sun fixed instead of the earth. The relative motions of the planets are the same in both systems ..." (p. 204), Kuhn, Thomas S. , ''The Copernican Revolution'' (Harvard University Press, 1957).</ref> but the Tychonic system fit the available data better than Copernicus system <ref>"This new geoheliocentric cosmology had two major advantages going for it: it squared with deep intuitions about how the world appeared to behave, and it fit the available data better than Copernicus's system did.." ''The Case Against Copernicus'' (Scientific American, Dec 17, 2013 |By Dennis Danielson and Christopher M. Graney).</ref>

 

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In regards to the stars, Tycho also believed that if the Earth orbited the Sun annually there should be an observable [[stellar parallax]] over any period of six months, during which the angular orientation of a given star would change thanks to Earth's changing position (this parallax does exist, but is so small it was not detected until 1838, when [[Friedrich Bessel]] discovered a parallax of 0.314 arcseconds of the star [[61 Cygni]]<ref>J J O'Connor and E F Robertson. [http://www-history.mcs.st-andrews.ac.uk/Biographies/Bessel.html Bessel biography]. [[University of St Andrews]]. Retrieved 2008-09-28</ref>). The Copernican explanation for this lack of parallax was that the stars were such a great distance from Earth that Earth's orbit was almost insignificant by comparison. However, Tycho noted that this explanation introduced another problem: Stars as seen by the naked eye appear small, but of some size, with more prominent stars such as Vega appearing larger than lesser stars such as Polaris, which in turn appear larger than many others. Tycho had determined that a typical star measured approximately a minute of arc in size, with more prominent ones being two or three times as large.<ref>The sizes Tycho measured turned out to be illusory -- an effect of optics, the atmosphere, and the limitations of the eye (see [[Airy disk]] or [[Astronomical seeing]] for details). By 1617, Galileo estimated with the use of his telescope that the largest component of [[Mizar and Alcor|Mizar]] measured 3 seconds of arc, but even that turned out to be illusory -- again an effect of optics, the atmosphere, and the limitations of the eye [see {{cite journal|url=http://www.leosondra.cz/en/mizar/|author=L. Ondra|title=A New View of Mizar|journal=Sky & Telescope|date=July 2004|pages=72–75}}]. Estimates of the apparent sizes of stars continued to be revised downwards, and, today, the star with the largest apparent size is believed to be [[R Doradus]], no larger than 0.057 ± 0.005 seconds of arc.</ref> In writing to Christoph Rothmann, a Copernican astronomer, Tycho used basic geometry to show that, assuming a small parallax that just escaped detection, the distance to the stars in the Copernican system would have to be 700 times greater than the distance from the sun to Saturn. Moreover, the only way the stars could be so distant and still appear the sizes they do in the sky would be if even average stars were gigantic — at least as big as the orbit of the Earth, and of course vastly larger than the sun. And, Tycho said, the more prominent stars would have to be even larger still. And what if the parallax was even smaller than anyone thought, so the stars were yet more distant? Then they would all have to be even larger still.<ref>Blair, 1990, 364. Moesgaard, 1972, 51.</ref> Tycho said<blockquote>Deduce these things geometrically if you like, and you will see how many absurdities (not to mention others) accompany this assumption [of the motion of the earth] by inference.<ref>Blair, 1990, 364.</ref></blockquote> Copernicans offered a religious response to Tycho's geometry: titanic, distant stars might seem unreasonable, but they were not, for the Creator could make his creations that large if He wanted.<ref>Moesgaard, 1972, 52. Vermij R., "Putting the Earth in Heaven: Philips Lansbergen, the early Dutch Copernicans and the Mechanization of the World Picture", Mechanics and Cosmology in the Medieval and Early Modern Period (M. Bucciantini, M. Camerota, S. Roux., eds.) Firenze: Olski 2007: 121-141, pages 124-125.</ref> In fact, Rothmann responded to this argument of Tycho's by saying <blockquote>[W]hat is so absurd about [an average star] having size equal to the whole [orbit of the Earth]? What of this is contrary to divine will, or is impossible by divine Nature, or is inadmissible by infinite Nature? These things must be entirely demonstrated by you, if you will wish to infer from here anything of the absurd. These things that vulgar sorts see as absurd at first glance are not easily charged with absurdity, for in fact divine Sapience and Majesty is far greater than they understand. Grant the vastness of the Universe and the sizes of the stars to be as great as you like — these will still bear no proportion to the infinite Creator. It reckons that the greater the king, so much greater and larger the palace befitting his majesty. So how great a palace do you reckon is fitting to GOD?<ref>Graney, C. M., "Science Rather Than God: Riccioli's Review of the Case for and Against the Copernican Hypothesis", Journal for the History of Astronomy 43, 2012: 215-225, page 217.</ref></blockquote>