This new cosmology, created by Nicolaus Copernicus in the 16th century fundamentally changed man's understanding of the world. Now the Sun was the center of the universe.
The heliocentric theory initially caused great conflict with the Church, which still saw the Earth as the center of the universe on account of the special position granted to man by God. Galileo Galilei, an Italian mathematician, physicist and astronomer, was assisted by the scholar Johannes Kepler in developing the heliocentric system further using the newly invented telescope for astronomical observation. He made important discoveries, for instance the four largest moons of Jupiter, the rings of Saturn, sunspots and mountains on the Moon.
The observations of Galileo and Kepler provided the basis for the calculations made by the British physicist Isaac Newton. With his discovery of gravitation, he explained how the planets remain in their stable orbits. He stated that all objects in space and on the Earth are affected by a special force called gravity. Newton became famous for this discovery.
Using this new knowledge, Edmond Halley became the first to calculate the elliptical course of a comet, which was later named after him.
Although no new cosmologies have since been put forward to challenge the established one, new and better telescopes have allowed astronomers to look ever deeper into space. For thousands of years mankind knew of the existence of only six planets, which were given the names of Roman gods. The solar system ended with Saturn.
In 1780 a new type of reflecting telescope was successfully built. The following year, F.W. Herschel used it to discover the seventh planet, Uranus.
In addition, dim and far away stars were sighted and measured. Planet surfaces could also be examined more closely.
A spectroscope, which could be used to determine chemical composition, surface temperature, etc., was developed around the middle of the 19th century. Around this time the eighth planet, Neptune, was discovered.
