In 1543, Nicolaus Copernicus published his book "On the Revolutions of the Heavenly Spheres," which proposed that the Earth and the other planets revolved around the Sun. This was a radical departure from the prevailing view that the Earth was the center of the universe. Copernicus's theory was based on his observations of the planets and his calculations of their orbits. He also argued that the observed motions of the planets could be explained more simply if they were assumed to be orbiting the Sun.
Copernicus's theory was met with much opposition from astronomers and theologians. However, it gradually gained acceptance, and it eventually led to the development of modern astronomy. The heliocentric model of the solar system is now universally accepted, and it has had a profound impact on our understanding of the universe.
The defective circle in Copernicus's model was the orbit of Mercury. Mercury's orbit was not perfectly circular, and it did not always follow the same path across the sky. This led to some confusion among astronomers, and it was one of the main objections to Copernicus's theory.
However, Copernicus was able to explain the observed motions of Mercury by assuming that Mercury's orbit was elliptical. This was a significant breakthrough, and it helped to convince other astronomers that Copernicus's theory was correct.
The defective circle in Copernicus's model changed history by helping to lead to the development of modern astronomy. It also showed that even the most brilliant scientists can make mistakes. However, it is important to remember that mistakes are a part of the scientific process, and they can often lead to important discoveries.