Beyond Saturn lay a final sphere with all the stars fixed to it that revolved around the other spheres. If the Sun is located at one focus of Earth's elliptical orbit, what is at the other focus? Compare heliocentrism; Ptolemaic system; Tychonic system. Homework 3 Flashcards | Quizlet Ptolemy included epicycles in his orbits. Ptolomy's model of the solar system was geocentric, where the sun, moon, planets, and stars all orbit the earth in perfectly circular orbits. d. Earth, Jupiter, and Saturn However, the paths of the Sun, Moon, and planets as observed from Earth are not circular. d. Venus' phases 1 m/s2 Observations of what astronomical events allowed astronomers to definitively determine that the heliocentric model of the solar system was correct? With this simple eccentric model Ptolemy explained the Suns varying motion through the zodiac. &=&\left( c-a\right) \left( b-a\right) \left( c-b\right) . a. e. empirical laws. b. Tycho Brahe The line connecting the planet and Sun sweeps out three areas labeled A, B, and C, during three different time intervals. You can judge for yourself as you study the subject of astronomy. Rejected by modern science, the geocentric theory (in Greek, ge means earth), which maintained that Earth was the center of the universe, dominated ancient and medieval science. Scientists of the 1500s and 1600s inherited a model of the universe whose basic features had been defined by Aristotle 2,000 years earlier. Ptolemy's geocentric model of the solar system | Britannica Brahe pointed out that solar observations Ptolemy claimed to have made in 141 are definitely not genuine, and there are strong arguments for doubting that Ptolemy independently observed the more than 1,000 stars listed in his star catalog. These observations helped Galileo to show that the heliocentric model was the more accurate model. Geocentric model | Definition, History, & Facts | Britannica a. Tycho Brahe made measurements of higher accuracy and showed the geocentric model was correct.