Question

What is the geocentric view of the universe and how did Galileo change that view ?

Answer 1

Hint: The geocentric view of the universe is based on the idea that the Earth is present at the centre of the whole universe. Galileo conducted certain observations on the phases of the Venus planet to prove that the Earth revolves around the sun.

Complete answer:
The geocentric view of the universe was first proposed and established by Ptolemy of Alexandria. The geocentric view of the universe states that the Earth is present at the centre of the universe. The Earth remains stationary and all the rest objects revolve around the Earth.

The Geocentric view of the universe proposed by Ptolemy showed the Earth at the centre and the Moon revolving closest to the Earth in a circular orbit. After the moon, it showed the planets Mercury and Venus. Then it showed the Sun revolving around the Earth in a circular orbit. After the Sun, it mentions the planets Mars, Jupiter and Saturn respectively, all moving in circular orbits.

However, this view was proved wrong by the observations of Galileo Galilei. Galileo observed the phases of the planet Venus. In the year $1600\;s$ , Galileo observed that Venus exhibits complete sets of phases like the moon.Venus showed a phase like a full moon when it is between Sun and Earth, and like a new moon when Sun is between the Earth and Venus, and the respective phases in between just like a complete moon cycle.

This system of phases was only possible if the Earth and Venus, both revolved around the Sun. Hence, Galileo proved the heliocentric system of the universe which stated that the Sun was present at the centre of the Universe and the planets revolve around the Sun.

Note: Even though the theory of heliocentric view which places sun at the centre of the universe was proved by Galileo Galilei, the theory was first proposed by the scientist Nicolas Copernicus in the year $1500\;s$ , where he challenged the Geocentric view of the Catholic Church.