Question

Scientific theories and models change over time. In the second century, Ptolemy, who lived in the Egyptian town of Alexandria, produced a mathematical representation based on observation of the known solar system. Ptolemy's model is called geocentric because the Earth was at the centre with the Sun and planets revolving in a series of circular orbits around the Earth. Copernicus reconstructed Ptolemy's model 1200 years later, producing the heliocentric model, with the planets orbiting the Sun. This model differs from models we see today thanks to the discoveries of other astronomers. How has the heliocentric model been amended?

A) Newer models show the speed of each planet as it spins on its axis in space.
B) The planets' orbits are not modeled as concentric circles around the Sun but rather as ellipses.
C) The order of the planets as the orbit the Sun has been modified due to technological advancements.
D) Astronomers have determined that the outermost planets have different shaped orbits than the innermost planets.

Answer 1

The heliocentric model has been amended with the discovery of ellipses for the planets' orbits and the differences in orbit shapes between inner and outer planets.

Step-by-step explanation:

One major amendment is that the planets' orbits are not modeled as concentric circles around the Sun but rather as ellipses. This was discovered by Johannes Kepler in the 17th century. Another amendment is that astronomers have determined that the outermost planets have differently shaped orbits than the innermost planets. For example, the outer planets have more elongated and inclined orbits, while the inner planets have nearly circular and coplanar orbits. The speed of each planet as it spins on its axis in space is not directly related to the heliocentric model. However, the heliocentric model provides a framework for understanding the overall motion of the planets around the Sun.