Students used to be taught that all the planets, stars, and the Sun moved around the Earth. Scientists used observations they had made to chart out the paths each planet must follow. The paths were very complicated. For example, the path Mars took around the Earth is shown below:

Question

Image from Astronomia Nova by Johannes Kepler, 1609

Using this model, scientists could predict fairly well where the planets would be and how they would move at any point in the near future.

Today, students are taught that all the planets move around the Sun and that the Earth spins on its axis once every 24 hours. Which of the following played the largest part in changing what students are taught?
A.
The world leaders changed their minds about what students should be taught.
B.
A scientist came up with a theory that the planets move around the Sun.
C.
The planets used to move around the Earth, but now they move around the Sun.
D.
Enough data was gathered to show how the planets move.

Answer 1

The option that played the largest part in changing what students are taught is:

B. A scientist came up with a theory that the planets move around the Sun.

This refers specifically to the work of astronomers such as Copernicus, Galileo, and Kepler, whose theories and observations led to the heliocentric model of the solar system. This model fundamentally changed our understanding of celestial movements and replaced the geocentric model (where everything revolved around the Earth).