• Astronomy is a natural science which is the study of celestial objects (such as stars, galaxies, planets, moons, asteroids and  comets). Astronomy is one of the oldest sciences. 

• The Solar System formed 4.6 billion years ago.The eight planets are: Mercury, Venus, Earth and Mars, Jupiter and Saturn, Uranus and Neptune.

• Mercury is the smallest and closest to the Sun of the eight planets in the Solar System, with an orbital period of about 88 Earthdays. 

• Venus is the second planet from the Sun,It has no natural satellite. It is named after the Roman goddess of love and beauty.

• Earth is the third planet from the Sun, the earliest life on Earth arose at least 3.5 billion years ago,including over 7.2 billion humans living in here.

• Mars is the fourth planet from the Sun and the second smallest planet in the Solar System, after Mercury. Named after the Roman god of war, it is often described as the "Red Planet".

• Jupiter is the fifth planet from the Sun and the largest planet in the Solar System. It is a giant planet, the Romans named it after their god Jupiter.

• Saturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Named after the Roman god of agriculture.

• Uranus is the seventh planet from the Sun. It is similar in composition to Neptune, and both are of different chemical composition Uranus's atmosphere, although similar to Jupiter's and Saturn's.

• Neptune is the eighth and farthest planet from the Sun in the Solar System Neptune is 17 times the mass of Earth, Neptune is similar in composition to Uranus.