PLANETS

PLANETS

   Planets are the large celestial bodies which orbits around the sun. They acquire round shape to maintain equilibrium. They not produce light on their own. They are usually made of rocks containing metals and minerals.

    Our solar system comprises of sun and eight planets.

• Terrestrial Planets :  Earth. Mercury. Venus. Mars.
• Gas Giants             :  Jupiter. Saturn. Uranus. Neptune.
• Dwarf Planets        : Ceres. Pluto. Haumea. Makemake. Eris.

INTERNATIONAL ASTRONOMICAL UNION proposed the three criteria that should be followed for a planet are:

• It is in orbit around the Sun.
• It has sufficient mass to assume hydrostatic equilibrium (a nearly round shape).
• It has “cleared the neighborhood” around its orbit.

                    Planets are revolving around the sun due to sun's gravity towards the planets. When there is supernova all planets are formed and maintained the same momentum. 

                   They will continue to rotate until and unless some external force acts on it. when the external force acts on the planet then the energy gets transferred to another object.

 Pluto has been removed from the planet list because it has not meet the third criteria that is it has not cleared its neighbourhood.

ORDER OF PLANETS

• Mercury
• Venus
• Earth
• Mars
• Jupiter
• Saturn
• Uranus
• Neptune