Important facts about various planets and satellites - solar system


  1. Inner planets Include Mercury, Venus, Earth and Mars.
  2. Outer Planets Include Jupiter, Saturn, Uranus and Neptune.


  • Mercury is the closest plane to the sun.
  • Mercury is an extremely hot planet.
  • The planet has no water on it.
  • Mercury planet has no gases like Co2  N2 H2 and O2 which can act as building blocks of life.
  • Mercury planet has no protective blanket like Ozone around it to prevent us from harmful radiations.


  • Venus is the second planet from the sun. This planet is nearest to the Earth and is also the brightest planet.
  • Venus is known as the ‘’Evening Star”.
  • Venus is surrounded by a thick cloud cover, hence known as  the “Veiled Planet” (veil  means unclear/cover).
  • Venus is like the Earth in size and mass and hence also known as the “Earth’s twin”.
  • Venus is a very hot planet.
  • Venus has no water on it.
  • There is no sufficient oxygen on the Venus.

The Earth: 

  • Earth is the largest of the inner planets.
  • The Earth is 23/12 tilted on its axis and thus makes 66/12 angle.
  • It takes 23 hours 56 minutes and 4.091 seconds to rotate on its axis.
  • It takes 365 days, 5 hours and 48 minutes to revolve around the sun.
  • Earth is known as the “watery planet” or the “Blue Planet” due to presence of huge amount of water.
  • Earth is the only known planet which provides sustenance or life on it.i it has large quantity of oxygen which supports life.
  • The Earth has all the essential elements like carbon (in the form of Co2), hydrogen(H2) , Nitrogen(N2) and Oxygen (O2) which act as building blocks for the origin of life.
  • The earth is neither too hot cold. It has the right temperature range carrying out the life – sustaining chemical reactions.
  • The earth has a lot of water in the form of lakes, rivers and oceans for the growth and survival of life.
  • The earth has enough oxygen gas in its atmosphere for the survival of living beings through breathing.
  • The earth has a protective blanket of ozone layer high up in its atmosphere to save life from harmful ultraviolet radiations coming from the sun.

The Moon: 

  • The moon is the only satellite of the earth.
  • It has a diameter of 3475 km. and its orbit is elliptical.
  • The maximum distance (apogee) of the moon from the earth is 4,06,000 km. and the minimum distance (perigee) is 3,64,00km.
  • It takes 27 days, 7 hours and 43 minutes to rotate on its axis (this period of about 27/12 days is called the sidereal months) and approximately the same period of time it takes to revolve around the earth. The moon’s period of revolution with reference to the sun is about 29,53 days(29 days, 12 hours, 44 minutes and 2.8 seconds) This period is called a synodic months.
  • Only 59 percent of the total surface of the moon is visible from the earth.
  • The bright part of the moon is full of mountains whereas the dark patches are low lying plains.‘sea of tranquility ‘, made of the plain of dust particles, is on the rear side of the moon, which always remain dark.
  • The highest mountain on the moon is Liebuity Mountain,which is 10,660 metre high.
  • The moon has no atmosphere, no twilight and no sound.
  • The temperature during daytime is about   100 oc and during night it drops down to about -180 o c.
  • The light from the moon takes 1.3 seconds to reach the earth.
  • The size of the moon is one-fourth (1/ 4th) the size of the earth.
  • Gravitational pull of Moon is one – sixth (1/ 6th) that of the Earth.
  • Mainly silicon, iron, magnesium etc. elements are found on the Moon‘s surface.
  • The study of the Moon is called “Selenology”
  • Moon is also known as the fossil planet.


  • Iron-rich red soil and pink sky of Mars give it the name “Redc planet”
  • Phobes and  Demos are two satellites of Mars.


  • Jupiter is the largest plant of the Solar System.
  • Jupiter is also known as winter planet as its average temperature is very low(148 o  c)

Saturn : 

  • Saturn is the second largest planet in the Solar System.
  • Saturn has bright concentric rings which are made up of ice and ice- covered dust particles which revolve around it.
  • Titan, the satellite of Saturn, is the largest satellite in the Solar System.


  • Uranus is about four times the size of the Earth. This plane appears greenish in colour because of methane gas present in its atmosphere.
  • Uranus was discovered in 1781 by Sir William Harsiel.
  • Uranus in the 7th planet from the sun .
  • Uranus is the first planet to have been discovered  by the use of a telescope.
  • Uranus is the third biggest planet of the solar system.
  • Uranus is extremely cold, the suface temperature being  -190 oC.
  • Uranus is surrounded by 5 rings namely,alpha,beta,gamma,delta andepsilon.
  • Uranus rotates from east to west on its axis, which is opposite to other planets.
  • The axis of Uranus has large inclination so that it appears to be lying down, hence it bears the name “A planet on its Side”.


  • Neptune is the 8th planet of the Solar System.
  • The temperature on the surface of Neptune remains low.
  • Neptune is very similar to Uranus and can be considered its twin.
  • Neptune is surrounded by methane rings of sub zero temperature.
  • Pluto is not planet now
  • On the basis of the new definition of planet given by the IAU (International Astronimical Union), the world’s top institution on space science research, leading astronomers participating in IAU ‘s meet at Pargue(Czech Republic) on August 24, 2006 , declared that Pluto would no longer remain a planet.
  • Under the IAU’s new guidelines, the number of planets in the Solar System has thus been reduced from nine to eight. Its merits mentioning here that, prior to this decision , Pluto had been holding the planetary status since its discovery in 1930 by Clyde Tobaugh.
  • Now, with the omission of Pluto from the Solar System, its membership has been restricted to the eight
  • “Classical” planets, namely Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.


Gets a Numerical Denomination
Weeks after it was demoted to a sub planetary status, Pluto was given a new name to reflect its new status as a dwarf planet in September 2006. The former 9th planet was assigned the asteroid number 134340 by the Minor planet Centre (MPC), the official organization responsible for collecting data about asteroids and comets in our Solar System.

Pluto’s companion satellites , Charon, Nix and Hydra are considered part of the same system and will not be assigned separate asteroid numbers Instead, they will now be called 134340 on 24th August, 2006 pluto was the outermost planet of the Solar System.

lam the creator and editor of Design Shard, I created this blog to post my inspirations, work, and free resources that I hope others find interesting too. See all posts by -- Sourav Mukherjee

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