Helocentric and Geocentric Review

What was the widely accepted model of the universe for many years, which placed Earth at its center?

• Heliocentric model

• Geocentric model

• Copernican model

• Newtonian model

What observational problem with planetary motion did the geocentric model attempt to explain using epicycles?

• The changing brightness of planets

• The phases of Venus

• The retrograde motion of planets

• The varying speed of planets

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Which historical figure proposed the heliocentric model, suggesting the Sun is at the center of the universe?

• Aristotle

• Ptolemy

• Nicolaus Copernicus

• Galileo Galilei

What shape did Johannes Kepler propose for the orbits of planets around the Sun?

• Perfect circles

• Ellipses

• Irregular spirals

• Straight lines