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Evolution of Earth

Evolution of Earth

       The earth was formed about 450 crore years ago from very vast clouds of gases and dust particles present in the form of disc around the sun. These particles of gases and dust collided and merged with each other to form small chunks of matter called planetesimals. These planetesimals then collided with each other and merged to form various planets including our earth. The gravitational force of earth was high, so it started attracting more planetesimals towards itself. When the planetesimals collided with earth, a large amount of heat gets produced. This resulted in rising the temperature of earth. Also decomposition of radioactive elements present in the earth produced enormous amount of heat. This enormous amount of heat caused the earth to melt after 80 crore years of its formation.

Layers Of Earth

Layers of earth:

       Subsequently, the earth started cooling and rearranged itself into three layers namely crust, mantle and core under the influence of gravity. During rearrangement, the heavy and medium weight materials (e.g. iron) sank down in the interior of earth and formed core and mantle respectively. While the lighter materials (e.g. silicon and aluminium) came up and formed crust of earth.

Test Your Understanding and Answer These Questions:

  1. What are planetesimals?

  2. How many years ago was earth formed?

  3. Name different layers of earth?

  4. What is structure of earth?

  5. What are crust, mantle and core?