Earth and Universe | Geography

Earth & Universe | Geography


  • In the Solar System, our Earth is a unique planet because of the life forms that exist on its surface.
  • Attempts to separate natural and anthropogenically induced variability in the Earth System have proved to be successful in many respects.
  • our understanding of the natural dynamics of the Earth System has advanced greatly.
  • It is now clear that global change is one of the paramount environmental issues facing humanity at present.

The Earth System

  • Our Earth’s position is very special in the solar family.
  • The Earth is placed at a distance from the sun that makes its position very conducive for the growth of living organisms.
  • The recipe of life is unknown, but likely ingredients were methane, carbon dioxide, ammonia and water in the atmosphere and seas of the young Earth.
  • The action of ultraviolet radiation or lightning could have combined these chemicals into amino acids, the building blocks of protein and of all living things.
  • Plants were the first life forms to colonize the early Earth, followed by the proliferation of humans and other animals.
  • These life forms are the biotic components of the Earth.
  • The Earth has two motions.
  • It rotates on its axis inclined at an angle of 23 ½0.
  • Due to this rotation day and night occur.
  • The Earth also on its inclined axis revolves around the Sun and thus produce seasons.
  • The seasons are classified based on temperature conditions. In a year, there are spring, summer, autumn and winter seasons.
  • The systems analysis helps to understand the Earth’s structure as a whole and also the functional interactions that exist between the components.
  • The lithosphere, hydrosphere and atmosphere are the abiotic components of the Earth. These components interact with each other and create the fourth component of the Earth, the biosphere.
  • Biosphere interacts with the abiotic elements and a number of ecosystems are created on the surface of the Earth. The Earth is considered a unique subsystem in the planetary system.

The Planetary System

  • Gases and dust surrounded our star, the Sun approximately 5 billion years ago.
  • Over time they condensed and formed planets.
  • The planetary system consists of eight planets
  • Mercury
  • Venus
  • Earth
  • Mars
  • Jupiter
  • Saturn
  • Uranus
  • Neptune
  • satellites
  • All these planets revolve around the Sun on their own axes.
  • Every planet has its own elements and mechanisms irrespective of their size.
  • Mercury, Venus, Earth and Mars are smaller in size.
  • They have large amounts of rocks and smaller amounts of gases.
  • These planets are called rocky planets.
  • Jupiter, Saturn, Uranus and Neptune are bigger in size.
  • They have small amounts of rocks and large amounts of gases are called Gaseous Planets.

The Solar System

  • The Sun is the main source of energy for the planetary system.
  • The Sun is a mixture of gases.
  • It consists of 92% hydrogen, 7.8% helium and 0.2% other gases.
  • The temperature on the surface of the Sun is 6,000 degrees Celsius and the temperature at the centre of the Sun is more than 15,000,000 degree Celsius.
  • The Sun shines as a consequence of the fusion of hydrogen into helium, which is constantly taking place in its core.
  • Astronomers call the Sun a “Big Fire Ball”. Scientists believe that the Sun will cease its function when the hydrogen is exhausted.
  • It is estimated that the Sun had enough hydrogen to burn for 10,000 million years (10 Billion years).
  • It has burnt already for 5,000 million years.
  • It is literally a middle-aged star.
  • The Sun and its components namely the planets form the Solar System.
  • This Solar System is a subsystem of the Universe.
  • The Universe consists of millions and millions of galaxies.
  • Solar System is part of one such galaxy known as the Milky Way.
  • The universe is considered as a general system that consists of many subsystems. These components interact with each other and create the Earth’s environment.

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