Geocentric and heliocentric universe

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Geocentric and heliocentric universe
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• Aristarchus was then faced with calculating an
  approximation for what is in our notation sin 3.
  He obtained the inequality
• 1/18 gt sin 3 gt 1/20
• and deduced that the sun was between 18 to 20
  times as far away as the moon. In fact at the
  moment of half illumination the angle between the
  moon and the sun is actually 89.50 and the sun
  is actually about 400 times further away than the
  moon.

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• heliocentric model A model of the solar system
  which is centered on the Sun, with the Earth in
  motion about the Sun
• cosmology The study of the structure and
  evolution of the entire universe.
• geocentric model A model of the solar system
  which holds that the Earth is at the center of
  the universe and all other bodies are in orbit
  around it. The earliest theories of the solar
  system were geocentric.

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• retrograde motion Backward, westward loop traced
  out by a planet with respect to the fixed stars.

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• Greek philosopher Aristotle (384322 b.c.) and
  were in nature, meaning that Earth lay at the
  center of the universe and that all other bodies
  moved around it.

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• Aristotle, and Plato before him, had taught was
  the perfect form the circle. The simplest
  possible descriptionuniform motion around a
  circle having Earth at its centerprovided a
  fairly good approximation to the orbits of the
  Sun and the Moon, but it could not account for
  the observed variations in planetary brightness
  or their retrograde motion.

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• epicycle A construct of the geocentric model of
  the solar system which was necessary to explain
  observed planetary motions. Each planet rides on
  a small epicycle whose center in turn rides on a
  larger circle (the deferent).

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• deferent A construct of the geocentric model of
  the solar system which was needed to explain
  observed planetary motions. A deferent is a large
  circle encircling the Earth, on which an epicycle
  moves.

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• Around a.d. 140, a Greek astronomer named Ptolemy
  constructed perhaps the best geocentric model of
  all time. Illustrated in simplified form in
  Figure 2.6, it explained remarkably well the
  observed paths of the five planets then known, as
  well as the paths of the Sun and the Moon.
  However, to achieve its explanatory and
  predictive power, the full required a series of
  no fewer than 80 distinct circles.

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• Aristarchus of Samos (310230 b.c.), proposed
  that all the planets, including Earth, revolved
  around the Sun and, furthermore, that Earth
  rotates on its axis once each day. This, he
  argued, would create an apparent motion of the
  sky

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• (c. 310-230 BC), Greek astronomer, first to
  maintain that the Earth rotates and revolves
  around the Sun. On this ground, Cleanthes the
  Stoic declared that he ought to be indicted for
  impiety.

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• Aristarchus' advanced ideas on the movement of
  the Earth are known from Archimedes and Plutarch
  his only extant work is a short treatise, "On the
  Sizes and Distances of the Sun and Moon." The
  values he obtained, by using geometry, are
  inaccurate, because of faulty observations.

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• Aristarchus found a more precise value for the
  length of the solar year. A lunar crater is named
  for him a peak in its centre is the brightest
  formation on the Moon.

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• Bruno, Giordano
• b. 1548, Nola, near Naplesd. Feb. 17, 1600, Rome

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• original name FILIPPO BRUNO, byname IL NOLANO,
  Italian philosopher, astronomer, mathematician,
  and occultist whose theories anticipated modern
  science. The most notable of these were his
  theories of the infinite universe and the
  multiplicity of worlds, in which he rejected the
  traditional geocentric (or Earth-centred)
  astronomy and intuitively went beyond the
  Copernican heliocentric (Sun-centred) theory,
  which still maintained a finite universe with a
  sphere of fixed stars.

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• Bruno is, perhaps, chiefly remembered for the
  tragic death he suffered at the stake because of
  the tenacity with which he maintained his
  unorthodox ideas at a time when both the Roman
  Catholic and the Reformed churches were
  reaffirming rigid Aristotelian and Scholastic
  principles in their struggle for the
  evangelization of Europe.

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PTOLEMY
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GALILEO
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TYCHO BRAHE
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KEPLER
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COPERNICUS
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HUYGENS
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NEWTON DEATH MASK
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MILLIKAN AND EINSTEIN