What Is Planet?

Planets these are solid celestial large bodies that are rotating around the sun. They are larger than any other bodies in our solar system. Planets are divided into two parties. Inner planet and outer planets. Inner planets include Mercury, Venus, Mars and Earth. These planets are also called rock giants. This is because they made up of rocks and iron. These inner planets are small compared to outer planets.

Inner planets include Jupiter, Saturn, Uranus and Neptune. These outer planets are larger than inner planets. They consist of hydrogen, helium and ice. The first two outer planets (Jupiter and Saturn) are called gas giants as their composition consist of the gases at large. The other two planets (Uranus and Neptune) are called ice giants as the made up of ice at large.

Current there are only eight planets in our solar system. Previous we believed that Pluto is one of these planets. In 2006 Astronomers under International Astronomical Union (IAU) removed Pluto as a planet. From there they provided three characteristics of planets as follows.

It must orbit the sun
It must have round shape from the effects of its own gravity
It is the dominant object in its region of space and has cleared the neighbourhood of its orbit of other objects.
(Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation)

Mercury is the closest planet from the sun in our solar. It is the smallest planets in our solar system. The second planet from the sun is Venus it is also called morning star. It is the brightest planet in the solar system. It is the hottest planet. This is because its atmosphere’s carbon dioxide is 90 larger than that of the earth. Its temperature is about 477oC. The earth is the only planet that believed to support life of the living organism. It is the third planet from the sun and only planet that contain water. Mars is the fourth planet from the sun.

Jupiter is the fifth planet from the sun. It is the largest planet in our solar system. Jupiter has more moons than any other planets. The sixth planet from our solar system is called Saturn. Its moon Titan has thicker atmosphere than any other satellite in our solar system. Saturn is the only planets that have a ring around it. The seventh and eighth planets are Uranus and Neptune respectively.
vThe path used by planets to orbit the sun is called orbit. The shape of the orbit is an elliptic shape. The time which a planet use to orbit the sun is depending on the distance from the sun. For example, mercury spends little time to orbit the sun while Neptune spends a lot of time than any other planets to orbit the sun.