Define with example: Planet, Satellite, Shooting star, Planetoid.

Hint: The solar system comprises the Sun, the eight planets, satellites, asteroids, comets, meteors and dwarf planets. The Sun is at the centre and surrounding it are the planets, asteroids, meteors, dozens of moons and comets.

Complete Step by Step Answer: There exist three to four major theories about the origin of the universe and the solar system, out of which Big Bang Theory is the most prominent one.
The planet is a celestial body that moves in an elliptical orbit around a star. There are eight planets in the solar system namely Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. These eight planes are further divided into two groups - the inner circle planets and the outer circle planets. The inner-circle planets are close to the sun and are made up of rocks. It comprises four planets namely Mercury, Venus, Earth and Mars. The outer planets are situated at a greater distance from the sun and are made up of liquids and gases, namely, Jupiter, Saturn, Uranus and Neptune.
Satellite is an object or a machine that orbits around a bigger object. There are two types of satellite, one is natural and the other one is artificial. An example of a natural satellite is the moon that orbits around the earth and an example of an artificial satellite is the International Space Station that is circling around the earth.
A shooting star is a meteor which is a streak of light that appears in the sky when a meteoroid enters the earth atmosphere with a high speed and usually burns up due to the friction. When a meteor without burning up, reaches the Earth surface is termed as a meteorite.
Planetoids are primitive bodies, also known asteroids mostly found between Mars and Jupiter. The circular chain of asteroids orbiting around the sun is called the asteroid belt.

Note: The Big Bang Theory, is also known as the Expanding Universe theory. According to this theory, with the passing of time, the galaxies move farther and farther apart, resulting in the widening or expanding of the universe. The big bang, according to scientists, occurred sometime between 10 to 20 billion years ago.