Planets of our Solar System

Planets of our Solar System

• There are eight planets in our solar system. ( Excluding pluto which now is a dwarf planet ).
• The sequence of planets according to their distance from the sun is
  1. Mercury
  2. Venus
  3. Earth
  4. Mars
  5. Jupiter
  6. Saturn
  7. Uranus
  8. Neptune.
• The sequence of planets according to their size (in descending order i.e. from big to small) is
  1. Jupiter
  2. Saturn
  3. Uranus
  4. Neptune
  5. Earth
  6. Venus
  7. Mars
  8. Mercury.
• A hypothetical ninth planet has been recently discovered by NASA named Carla.
• Planets are classified into the two groups –  inner and outer planets

Inner planet	Outer planet
They are called as terrestrial or rock planets. They are nearer to the Sun.	They are called as Jovian or Gaseous. planets. They are far away from the Sun.
They include: Mercury, Venus, Earth and Mars	They include: Jupiter, Saturn, Uranus and Neptune.

1. Mercury

   • Nearest planet to Sun.
   • This planet has no gas water or gases on it.
   • Since Mercury does not have any atmosphere, it’s day is very hot whereas night is very cold.
   • Period of Rotation (Day) : 58 Earth Days, Period of Revolution (Year) : 87 Earth days.

2. Venus

   • Nearest planet to Earth.
   • Brightest Planet.
   • Also known as “Evening Star” as well as “Morning Star”.
   • Known as the “Veiled Planet”.
   • Also known as the “Earth’s twin” or Earth’s sister planet 
   • This planet rotates clockwise like Uranus.
   • Hottest planet of Solar System.
   • Venus has no water on it. 
   • It has the densest atmosphere of the four terrestrial planets. The atmospheric pressure at the planet’s surface is almost 92 times that of Earth.
   • A day on Venus is equivalent to 243 earth days.
   • A year on Venus is 224 earth days. Venus’s day last longer than it’s year.
   • Period of Rotation (Day) : 243 Earth Days, Period of Revolution (Year) : 224 Earth days.

3. Earth

   • Known as “Blue Planet” and “Watery Planet” .
   • This is where we live. 🙂
   • Earth is the only known planet which provides sustenance or life on it.
   • 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.
   • It has one natural Satellite – names “Moon”. 

4. Mars

   • Because of its Iron-rich red soil and pink sky, it is also know as “Red Planet” .
   • Phobes and Demos are two satellites of Mars.
   • Mars is named after Roman god of war.
   • Mar’s Olympus Mons (shield volcano), is the largest volcano and the highest known mountain (24 km) in the Solar System.
   • Period of Rotation (Day) : 1.025 days Earth Days, Period of Revolution (Year) : 687 days Earth days.

5. Jupiter

   • largest planet in the Solar System. 
   • It is composed mostly of gas and liquid swirling in complex patterns with no solid surface.
   • Jupiter has 79 moons ( Natural satellite ).
   • Natural satellite of Jupiter named,  Ganymede, is the largest satellite in the Solar System.
   • Galileo discovered four satellites of Jupiter including Ganymede (Europa, Ganymede, and Callisto ). 
   • Jupiter is also known as Winter Planet because of it’s low average temperature.
   • Rotation speed of Jupiter along it’s axis is very high because of it the planet’s shape is that of an oblate spheroid (slight bulge at the equator).
   • Period of Rotation (Day) : 9.9 Earth hrs, Period of Revolution (Year) : 11.9 Earth Years.

6. Saturn

   • Saturn has bright concentric rings which are made up of ice and ice-covered dust particles which revolve around it.
   • After recent discovery of few satellites of Saturn, now in solar system, Saturn has most number of discovered natural satellites.
   • Titan is the largest satellite of Saturn and second largest satellite of solar system. 
   • Period of Rotation (Day) : 10.7 Earth hrs, Period of Revolution (Year) : 29 Earth Years.

7. Uranus

   • Uranus is about four times the size of the Earth.
   • This planet appears Greenish in colour because of methane gas present in
     its atmosphere.
   • Uranus is the first planet to have been discovered by the use of a telescope.
   • Like Venus, Uranus also rotates from east to west (  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”.
   • Period of Rotation (Day) : 17 Earth hrs, Period of Revolution (Year) : 84 Earth Years.

8. Neptune

   • Neptune is very similar to Uranus and can be considered as its twin.
   • In Solar system this is the farthest planet from Sun.
   • Period of Rotation (Day) : 16 Earth hrs, Period of Revolution (Year) : 164 Earth Years.

Dwarf planets of solar System

• There are 5 officially recognized dwarf planets in our solar system, they are
  • Ceres
  • Pluto
  • Haumea
  • Makemake and
  • Eris.
• With the exception of Ceres, which is located in the asteroid belt, the other dwarf planets are found in the outer solar system.
• Pluto
  • As per the plant definition of IAU (International Astronomical Union), Pluto is no longer a planet from August 24, 2006. It’s now a Dwarf planet. 
  • It is the largest dwarf planet of solar system.
  • Charon is Pluto’s largest moon.