Solar System

The Solar System comprises the sun 8 planets,their moon and other stellar objects, which developed from the condensation of gases and other lesser bodies.The sun is at the centre of the solar system and all the planets revolve around it in elliptical orbit.

Components of Solar system

Our System system consists of:

  • The sun, eight planets and their respective satellites.
  • Interstellar debris such as asteroids, meteoroids, comets.
  • The electrically charged gases, called Plasma.
  • Interplanetary dust particles.
  • The components of Solar System other than dwarf planets and satellites are smaller Solar system.

The Sun

  • The sun consists of more than 99% of the mass of the Solar System and due to this, the Sun exerts immense gravitational pull to keep the planets rotating around it in definite elliptical orbit.
  • The sun is the major source of energy of the Solar system.The energy is provided by the nuclear fusion reaction, that converts hydrogen into helium in the core of the sun.
  • Superimposed on Sun’s white light are hundred of dark lines called Fraunhofer lines.

Some concepts associated with Sun

  • Solar Winds The sun is continuously emitting streams of proton in all directions either as spiral streams called Solar Wind or bouts of incandescent material called Solar Flares.
  • Aurora The constituent particles of the solar wind are trap by the Earth’s upper atmosphere as Aurora. Described as Aurora Borealis in the Northern hemisphere and Aurora Australis in Southern hemisphere.
  • Plages and Sunspots The surface of the sun is continuously changing. Bright spots are Plages and dark spots are Sunspots. The Sunspots are cold and dark regions on the Sun’s surface with a periodicity of 11 years. These spots greatly influence the global climate.

Read More- Layers of Atmosphere


  • A planet is a heavenly body that moves in an orbit around a Star, such as the Sun.
  • There are 8 planets of the Stars and all the planets moves around a Sun in the fixed path.


It is the innermost and smallest planet in the solar system.

  • Mercury is nearest to the Sun.
  • Rotation Period 58.65 days.
  • Revolution period 88 days
  • It has no satellite.
  • Has the highest diurnal range of temperature.
  • Has the shortest year.


  • Also known as Earth’s twin,Morning star, Evening star.
  • Brightest heavenly body after Sun and Moon because of 70% albedo.
  • Venus is closest planet to Earth.
  • Hottest planet in our Solar system because of 97% CO2.
  • Slightly smaller than Earth.
  • Rotates clockwise and has no satellite.
  • Slowest rotation period in our Solar system (257 days).
  • Almost equal rotation and revolution (224.7 days).


  • Mars is the fourth nearest planet to the Sun.
  • Mars is called Red Planet because it appears as a reddish.
  • Revolution period 24.6 hrs.
  • It has two satellites Phobos and Deimos.
  • It has signs of water.
  • There is possibility of life.


  • Largest of all planets almost 11 times of Earth.
  • Called Lord of heavens.
  • A great red spot is detected on it.
  • Fastest rotation time in our Solar System (9.8hrs).
  • Revolution Period 12 yrs.
  • More that 39 satellites (prominent is Titan). It has the largest number of natural satellites or moons.
  • It has system of ring (3 well defined).


  • Identified as a planet in 1781 by William Herschel.
  • Rotates from North to South as it is inclined at an angle of 98° to its orbit.
  • Revolution Period 84 years.
  • Rotation Period 10.8 years.
  • Like Saturn it is also surrounded by a system of 9 faint rings.
  • It has 21 satellites.


  • Appears as ‘Greenish star’ because of presence of Methane.
  • Revolution Period 165years.
  • Revolution Period 15.7 days.
  • Discovered by JG Galle of Berlin in 1846.
  • Prominent satellite are ‘Trion and Nereid’.
  • Uranus and Neptune are called jovian twins.


Pluto is no longer consider a planet in our solar system.Pluto orbits beyond the orbit of Neptune. It is much smaller than any of the official Planets and now classified as a Dwarf Planet. It is the second dwarf planet in the solar system.In roman mythology, Pluto is the God of underworld.

Read More- Facts about Earth


  • Comet is a member of the Sun’s family, part of the Solar system.
  • Comet travels on a path or elliptical orbit around the sun on a regular schedule.
  • It has a head and a tail. Its tail originates once it gets closer to the sun.
  • Originate from a huge cloud the ‘oort cloud’ that is thought to surround the Solar system.
  • The brightest part of the comet is head.
  • Made up of solid matter combined with gases.


  • Asteroids or minor planets circle in a broad belt between the orbits of Mars and Jupiter.
  • It is the debris left over from the formation of inner planets. Also called ‘Planetoids’ or small planets.
  • They are chunks of rocks.


Meteoroids are small bodies that travel through space.Meteoroids are smaller that Asteroids, most are smaller than the size of a pebble. Most meteoroids come from asteroids that broke by impacts with other asteroids. Other meteoroids come from the Moon, from comets and from the planet Mars.


A meteor is a meteoroid that has entered the Earth’s atmosphere, usually making a fiery trail as it falls. It is sometimes called a shooting star.

The friction between the fast moving meteor and the gas in the Earth’s atmosphere causes intense heat, the meteor glows with heat and then burns. A meteor glows with heat and then burns. A meteor shower is a phenomenon in which many meteors fall through the atmosphere in a relatively short time and in approximately parallel trajectories.


Only 59% of moon surface is directly visible from Earth.It takes 27days, 7hrs, 43min and 11.47sec to complete one revolution around the Earth.

  • Rotates on its axis in exactly the same time as that in revolution. That is why we see only one side of the Moon.
  • Circumference 11000km.
  • Distance from Earth 382200km.
  • Moon light takes 1.3sec to reach Earth.


Stars are heavenly bodies made up of hot burning gases, thus shining by their own light.

If the star is bigger than the Sun but not more than twice as big, it will turn into a Neutron Star or Pulsar. They are formed due to novate or super novae explosion.

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