Dear Readers, welcome to Awareness Adda. today article is Solar System this is one of the main topics in Geography. which is helpful for your examinations. here we give you more important notes on Solar System. Before that small discussion about Geography.


            The term Geography has evolved from Greek words Geo( the Earth) and Graphein (to write). Geography is the study of the earth as a home for mankind. The subject matter of geography is very vast and complex. there have been two approaches to the study of the discipline. the regional approach and the systematic approach.The regional approach is based on the concept of unique and it implies that no two places or areas are alike. Therefore, the approach to study geography should emphasize on identifying differences between areas. The nature of study should be descriptive. This approach does not allow generalizations or formulation of laws or theories.The systematic approach is based on the concept of universality and it implies that though all places and areas differ from each other. there are similarities between various parts of the world. supporters of systematic approach emphasize that the aim of geographers should be to identify similarities between areas and laws and theories should be formulated to seek explanations of geographical patterns and phenomena.according to this approach geography is not a descriptive but analytical discipline.

            Before going to solar system we need to know some important definitions. those are given below.

Universe: –

            The universe is commonly defined as the totality of everything that exists including all physical matter and energy, the planets, stars, galaxies and the contents of intergalactic space.

Note: –

  • The study of the universe is known as Cosmology.
  • Cosmology= Cosmos (the universe) + logos (science)
  • The universe has no limit.

Galaxy: –

  • A galaxy is a large system of Billions of stars, which also contains a large number of gas clouds ( mainly of hydrogen gas) and dust, isolated in space from similar systems.
  • There are about 100 billion galaxies in the universe, and each galaxy has an average 100 billion stars so the total number of stars in the universe is 1022 stars.
  • The milky way galaxy is the home of the Earth and our Solar System.It is spherical in shape.
  • This milky way is formed in 5billion years after the Big Bang.
  • Latest known galaxy is the Dwarf Galaxy.
  • Origin of the universe is explained by the Big Bang Theory, formulated and proposed by the Belgium astronomer and cosmologist Georges Lemaitre.
  • Andromeda is our nearest Galaxy.

What is Big Bang Theory?

  • All the matter in the universe was originally a concentrated lump called a primeval atom.
  • Big Bang was an explosion that occurred 15 billion years ago, leading to the formation of galaxies of stars and other heavenly bodies.
  • since then, all the galaxies have been flying away from one another causing expansion of the universe.


            Clumps of dust and gas in a nebula come together due to gravity and form stars, stars are made of hot burning gasses. they emit light of their own and are very large and very hot. Light takes about 4.3 years to reach us from the next nearest star Proxima Centauri.



  • The Earth is a member of a group of celestial bodies called the solar system. our solar system consists of a star(sun), and 8 planets and countless fragments of leftovers called asteroids, comets, and satellites of the planets.
  • planets have no light of their own and all of them except Venus and Uranus Rotate upon their axis from west to east. Venus and Uranus rotate upon their axis from east to west.
  • some planets have the satellites which are revolving around the planets
  • The sun which is the largest body of the solar system is also the center of the solar system.
  • The view considering the sun as the center of the solar system was given by Copernicus and is called the Heliocentric view.
  • as previous, all of us believes that Earth was considered the center of the solar system was given by Aristatil This view called the geocentric view.
  • The gravitational pull of the sun keeps all the planets and other objects revolving mainly around it. thus, the motion of all the members of the solar system is governed mainly by the gravitational force of the sun.
  • In solar system the nearest planet to the sun is Mercury and the farthest planet from the sun is Neptune.(not Pluto).
  • The solar system size has been estimated to at about 105 A.U.
  • The solar system is dominated by the sun which accounts fro almost 99.9% of the matter in the whole solar system.
  • The sun is also the source of all the energy in the solar system.
  • Pluto is a dwarf planet.
  • Mercury, Venus, Earth, Mars are called terrestrial planets and Jupiter, Saturn, Uranus, and Neptune are called gaseous planets.

            In next article we will discuss the planets, stars etc.. If you follow us you surely a good score well in your examinations. you will get more important notes on Awareness Adda.all the best my dear friends.

            Allways remember that “If you don’t practice you don’t deserve to win“. so practice well. All The Best.