General Awareness - SPLessons

Solar System

Chapter 30

SPLessons 5 Steps, 3 Clicks
5 Steps - 3 Clicks

Solar System

shape Introduction

The Solar System is the gravitationally bound planetary system of the Sun and the objects that orbit it, either directly or indirectly. The Sun can be treated like a star, the largest are the eight planets, with the remainder being smaller objects, such as the five dwarf planets and small Solar System bodies. The article Solar System is very useful topic in several competetive exams.

shape Solar System

Solar System – Planets:

Earth is our living planet. Like the same way, Earth also exists in its home with other 7 planets. Our solar system consists of an average star SUN.

The Planets are listed as below

  • Mercury

  • Venus

  • Earth

  • Mars

  • Jupiter

  • Saturn

  • Uranus

  • Neptune

  • and Pluto.


Composition Of The Solar System:

  • Sun: 99.85%

  • Planets: 0.135%

  • Comets: 0.01%

  • Satellites: 0.00005%

  • Minor Planets: 0.0000002%

  • Meteoroids: 0.0000001%

  • Interplanetary Medium: 0.0000001%


Solar System – Sun:

  • The only star in our solar system and powerhouse of the solar system.

  • Composed of Hydrogen (73%), Helium (25%) gases and other metals.

  • Sun carries almost 99% mass of our solar system.

  • Approximately 15 crore Kilometres further away from Earth.

  • It takes around 8 minutes 30 seconds for light at the speed of 3 lakh Km/sec to reach the earth.

  • Temperature at surface = 5800 K or 5600 degree Celsius.

  • Temperature at the centre = 15.7 million K


Solar System – Mercury:

  • Closest planet to the Sun and very hot planet.

  • Smallest planet in the solar system with a diameter of 4900 Km.

  • Fastest Planet with speed of 172500 Km per hour to complete revolution around Sun in 88 days.

  • The planet with no water and gases like Nitrogen, Hydrogen, Oxygen and Carbon Dioxide.


Solar System – Venus:

  • Hottest planet in the solar system with the surface temperature of 478 degree Celsius.

  • Also known as Earth’s Twin.

  • It is because of similarity in size and mass between Venus and Earth.

  • One of the two planets in the solar system which rotate around the axis in a Clockwise direction.

  • Brightest Star in the Solar system.

  • It can be seen in morning and evening with open eyes. So known as Evening Star and Morning Star.


Solar System – Earth:

  • The only Planet to give support to life with a pleasant atmosphere.

  • Also known as Blue Planet because of the presence of water on it.

  • It has one natural satellite named Moon.


Solar System – Mars:

  • Known as Red Planet because of Iron-rich red soil.

  • Second smallest planet in the solar system after Mercury.

  • Has two natural moons Phobos and Deimos.

  • Has thin atmosphere and surface with valleys, craters, deserts and ice caps etc.

  • Olympus Mons – Largest volcano and the tallest mountain in solar system lies on Mars.


Solar System – Jupiter:

  • Largest planet of the solar system with the shortest rotation

  • Has atmosphere filled with Hydrogen, Helium and other gases

  • The third brightest object in the night sky after the Moon and Venus.

  • Great Red Spot, a giant storm in the solar system exists on this planet.

  • Has at least 69 moons, including 4 large Galilean Moons “Io, Europa, Ganymede, and Callisto” which were discovered by Galileo. “Ganymede” is the largest among them. It has an unclear ring around it.


Solar System – Saturn:

  • Second largest planet in the solar system and a gas giant.

  • Has bright and concentric rings around it which are made up of tiny rocks and pieces of Ice.

  • Saturn can float on water because it has less density than water.

  • Has at least 62 moons and Titan is the largest among them.


Solar System – Uranus:

  • Has the third- largest planetary radius and fourth largest planetary mass in the Solar system.

  • Greenish in colour.

  • Discovered by William Herschel in 1781.

  • Known as “Ice Giant”.

  • The atmosphere of Uranus is composed of Hydrogen and Helium primarily, but it also contains more water, ammonia etc.

  • Has coldest planetary atmosphere in the solar system.

  • Rotates clockwise on its axis like Venus but unlike other planets Has at least 25 moons.

  • Famous moons- Miranda, Ariel and Umbriel


Solar System – Neptune:

  • Farthest planet from the Sun.

  • It is also Ice Giant.

  • Atmosphere primarily composed of Hydrogen and Helium. Bluish in colour because of Methane.

  • Fourth largest planet and the third most- massive planet in the solar system

  • Discovered by Johann Galle and Urbain Le Verrier in 1846.

  • The only planet in the solar system found by Mathematical Predictions.

  • Has known 14 satellites.

  • Famous moon – Triton.


Solar System – Pluto:


  • As per the new definition of Planets determined by International Astronomical Union (IAU), Pluto has been omitted from the list of planets in 2006.

  • Pluto is considered as a dwarf planet (size between planets and asteroids) now and it is a member of Kuiper Belt.

  • Kuiper Belt is a spherical boundary outside the orbit of Neptune containing a number of asteroids, rocks, and comets.


Solar System – Asteroids:


  • These are small objects; rocks (mostly debris) revolve around the Sun.

  • They are mostly found in the Asteroid Belt which lies between the orbits of Mars and Jupiter. These are also known as Minor planets.

  • Ceres, Vesta, Psyche are some famous and largest asteroids in the solar system.


Meteors and Meteorites:

  • These are also known as Shooting stars.

  • Meteors are the small-sized rocky material which is generally formed due to asteroid collision and approaching the earth.

  • Because of Earth’s atmospheric layers, these small rocks burn before reaching the surface.

  • But there are some meteors which do not burn completely and land on Earth’s surface. They are called as Meteorites.

  • Willamette, Mbozi, Cape York, and El Chaco are some meteorites found on the Earth.

  • Lonar lake, Maharashtra in India is supposed to be created by a meteor impact in Pleistocene Epoch.


Solar System – Comets:

  • These are shiny, luminous Tailed Stars. These are rocky and metallic materials surrounded by frozen gases.

  • These are generally found in Kuiper Belt. They travel towards the Sun. Their tail faces opposite of the sun and head faces towards the Sun.

  • They become visible when they travel close to the Sun.

  • Halley comet is famous which appeared last time in 1986 and which reappears after every 76 years


shape Quiz

1. When does the distance between the sun and the earth is minimum?

    A. January 3
    B. June 21
    C . Sepetember 22
    D . December 22


Answer: Option A


2. When the sun is nearest to the earth, the earth is said to be in?

    A. Aphelion
    B. Apogee
    C . Perigee
    D . Perihelion


Answer: Option D

3. When does the earth is at its maximum distance from the sun?

    A. January 31
    B. July 4
    C . September 23
    D . December 22


Answer: Option B

4. When is the rate of rotation of the earth is highest on its axis?

    A. January 3
    B. December 22
    C . July 4
    D . It never changes


Answer: Option D

5. The International Date Line is?

    A. Equator
    B. 0° longitude
    C . 90° east longitude
    D . 180° longitude


Answer: Option D

6. The difference between solar day and sidereal day is?

    A. Both are equal
    B. Solar day longer than sidereal day
    C . Solar day shorter than sidereal day
    D . None of the above


Answer: Option B

7. The average distance between ……… and ………… is called one astronomical unit.?

    A. Earth and sun
    B. Earth and moon
    C . Sun and moon
    D . Sun to Pluto


Answer: Option A

8. What percentage of the surface of the moon is visible from the earth?

    A. More than 75%
    B. 50%
    C . 100%
    D . About 59%


Answer: Option D

9. The unit of measurement of the distance of stars from the sun is called?

    A. Light year
    B. Fathoms
    C . Nautical miles
    D . Nano meters


Answer: Option A

10. Which of the following is the largest producer of Coco in Africa?

    A. Ghana
    B. Sudan
    C . Nigeria
    D . Ivory Coast


Answer: Option A