The word planet means 'wanderer'. This is because the planets appear to move around non-stop in the night sky.
A planet is a huge celestial body that revolves around the Sun in fixed orbits. The planets have no light of their own, but they reflect the light of the Sun.
There are 8 planets in our solar system– Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. All these planets revolve around our Sun.
Planets have other bodies that orbit them. These are called satellites. Moon is a satellite of Earth. Mercury and Venus are the only two planets that have no satellites.
The first four planets- Mercury, Venus, Earth and Mars are made of rocks. Their inner core is made of metal, so they are called rocky planets.
The next four planets—Jupiter, Saturn, Uranus and Neptune are made up of gases such as hydrogen and methane and are massive compared to the rocky planets. These planets are called gas giants.
In size, Mercury is the smallest and Jupiter is the largest planet in our solar system. Mercury is the closest planet to the Sun and Neptune is the farthest planet from the Sun.
Planets also do not twinkle like stars because they are very close to our earth. With a good telescope at the right time, we can see some planets from Earth itself..
5 planets can be seen from Earth with the naked eye– Mercury, Venus, Mars, Jupiter and Saturn. Uranus and Neptune were discovered after the invention of telescopes.
All the planets rotate on their axis in the same way as the Earth rotates once on its axis in 24 hours. The time taken by a planet to make one revolution around the Sun is called its 'period of revolution'.