SOLAR SYSTEM

SOLAR SYSTEM

•      The solar system comprises of the sun and eight planets revolving round the sun, many satellites revolving around their respective planets, thousands of comets and billions of meteoroids.


•      Planets (in the increasing order of their distance from the Sun)

1.   Mercury


2.   Venus


3.   Earth


4.   Mars


5.   Jupiter

Geography for Competitive Exams (RRB,SSC,UPSC,etc)

ORIGIN OF THE EARTH

Earth formed from a small part of the sun, it originated as a hot gaseous mass, which on cooling, turned first into a liquid and then into solid mass.

Gaseous Hypothesis Theory – Kant

Nebural Hypothesis Theory – Laplace

Tidal Hypothesis Theory – Jeans and Jeffreys

•      The denser matter forms the central part of the earth and the

INVENTORS & DISCOVERERS

Simple Microscope – Antony van Leeuwenhoek

Compound Microscope – Zacharias Janssen or Sacharias Jansen

Electron Microscope – Max Knoll and Ernst Ruska

Telescope – Galileo Galilei

DNA Model – Watson and Crick

Law of Heredity – Gregor Mendel

Vitamins - Kazimierz Funk or Casimir Funk