THE EARTH AND THE SOLAR SYSTEM

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THE EARTH AND THE SOLAR SYSTEM 

Solar system is the group of heavenly bodies comprising the sun and the nine planets.

The origin of the Solar System

Theories

A theory is a set of reasoned ideas intended to explain facts or events

  1. Passing Star Theory
  • A star with a greater gravitational pull passed near the sun
  • It attracted large quantities of gaseous materials from the sun
  • The materials split, cooled and condensed to form planets
  • The planets were set in orbit by the passing star

Weaknesses

  • Doesn’t explain the origin of the sun and star.
  • Minimal chance of a star approaching another
  • Materials would disperse than condense
  1. Collision Theory
  • Star with greater gravitational pull passed near the sun
  • It attracted large quantities of gaseous materials
  • The materials split into portions
  • Large portions collided with smaller ones and swept them to form planets.

The weaknesses are the same as the passing star’s Theory.

  1. Nebula Clod Theory
  • There was a slowly rotating cloud of dust and gas called Nebula
  • It cooled and began to contact
  • Rotation speed increased and successive rings of gaseous materials were formed.
  • The rings condensed to form planets
  • The central gaseous material remained as the sun

Evidence

  • Rotation and revolution of planets in anticlockwise direction Weakness

The origin of nebular is not explained.

  1. Supernova/explosion Theory
  • There was a violent explosion of a star.
  • A cloud of dust (nebular) remained from the star.
  • There was fast movement of the cloud due to the force of explosion.
  • Rotation speed increased due to gravitational attraction
  • The cloud flattened into a disc.
  • The matter began to accumulate towards the centre to form a proto-sun which later began to shine.
  • The rest of the cloud collapsed to form planets.

Weaknesses

  • Doesn’t explain the origin of the star

• Doesn’t explain the cause of explosion

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