<P> In 1838, astronomer Friedrich Wilhelm Bessel measured the parallax of the star 61 Cygni successfully, and disproved Ptolemy's claim that parallax motion did not exist . This finally confirmed the assumptions made by Copernicus, provided accurate, dependable scientific observations, and displayed truly how far away stars were from Earth . </P> <P> A geocentric frame is useful for many everyday activities and most laboratory experiments, but is a less appropriate choice for solar - system mechanics and space travel . While a heliocentric frame is most useful in those cases, galactic and extra-galactic astronomy is easier if the sun is treated as neither stationary nor the center of the universe, but rotating around the center of our galaxy, and in turn our galaxy is also not at rest in the cosmic background . </P> <P> Albert Einstein and Leopold Infeld wrote in The Evolution of Physics (1938): "Can we formulate physical laws so that they are valid for all CS (= coordinate systems), not only those moving uniformly, but also those moving quite arbitrarily, relative to each other? If this can be done, our difficulties will be over . We shall then be able to apply the laws of nature to any CS . The struggle, so violent in the early days of science, between the views of Ptolemy and Copernicus would then be quite meaningless . Either CS could be used with equal justification . The two sentences,' the sun is at rest and the Earth moves', or' the sun moves and the Earth is at rest', would simply mean two different conventions concerning two different CS . Could we build a real relativistic physics valid in all CS; a physics in which there would be no place for absolute, but only for relative, motion? This is indeed possible!" </P> <P> Despite giving more respectability to the geocentric view than Newtonian physics does, relativity is not geocentric . Rather, relativity states that the Sun, the Earth, the Moon, Jupiter, or any other point for that matter could be chosen as a center of the solar system with equal validity . For this reason Robert Sungenis, a modern geocentrist, spent much of Volume I of his book Galileo Was Wrong: The Church Was Right critiquing and trying to unravel the Special and General theories of Relativity . </P>

Which of the following astronomers supported the earth-centered system