Earth’s Original Atmosphere

• Important features Earth has for supporting human life is the composition (description of what a substance or object is made of) of the atmosphere- wasn’t always suitable for human life.
• When Earth was first formed, it was a ball of molten rock orbiting the sun and the atmosphere was made up of carbon dioxide, water vapour and ammonia - most likely expelled from volcanoes.
• Theory for formation of the Earth’s original atmosphere is that it was formed by decomposition of different minerals in the molten rock.
• Air we breathe today is very different from that of the early (primary) atmosphere - four main gases were present then:

  • Carbon dioxide (CO2)
  • Water vapour (H2O)
  • Methane (CH4)
  • Ammonia (NH3)