Earth-Centered Modal
Many early Greek scientists thought the planets, the Sun, and the moon were fixed in separate spheres that rotated around Earth. The stars were thought to be fixed in another sphere that also rotated around Earth. This is called the Earth-centered model of the solar system. It included Earth, the Moon the Sun, five planets -Mercury, Venus, Mars, Jupiter, and Saturn -and the sphere od stars.

Sun-Centred Model
People believed that idea of an Earth-centred solar system for centuries. Then in 1543, Polish astronomer Nicholas Copernicus published a different view. Copernicus stated that the Moon revolved around the Sun. he also stated that the daily movement of the planets and the stars was due to Earth�s rotation. This is the Sun-centred model of the solar system. Using his telescope, Italian astronomer Galileo Galilei observed that Venus went through a full cycle of phases like the Moon�s, which could be explained only if Venus were orbiting the Sun. From this, he concluded that Venus revolves around the Sun and that the Sun is the centre of the solar system.

Modern View of the Solar System
We now know that the solar system is made up of nine planets, including Earth, and many smaller objects that orbit the Sun. The solar system includes a huge volume of space that stretches in all directions from the Sun. The Sun contains 99.86% of the mass of the solar system. Because of its gravitational pull, the Sun is the central object in the solar system. All other objects in the solar system revolved around the Sun.