Sun is the biggest star in the solar system and consists of 99.86% of all the mass of the solar system. It is located in the centre and is a sphere of hot plasma. Continuous nuclear reactions take place in its core which radiates energy in the form of light and infrared radiation.
The solar system consists of eight planets, namely, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Mercury is closest to the sun and also the smallest planet. It has no natural satellites.
Asteroids are big and irregular shaped pieces of carbon, rock or metal which can be found mostly in the asteroid belt, orbiting the Sun between Mars and Jupiter. These are also often called minor planets.
These are small and irregular shaped objects composed of ice. It is believed that they generally come from the Kuiper belt. When comets come close to the Sun, due to the heat the ice vaporizes and leaves a beautiful tail behind them.
The objects that revolve around the planets in the same direction as that of the planet are known as satellites. Moon is Earth's natural satellite. Satellites can also be man-made known as artificial satellites.
A star is a celestial object that consists of a luminous spheroid of plasma which is bound by its own gravity. During the night, they are easily visible with a naked eye. These are grouped into constellations and asterisms.
1 AU (Astronomical Unit) = 149,598,000 km