The Early Atmosphere

• Earth's first atmosphere 4.6 billion years ago was most likely comprised of hydrogen and helium (two most abundant gases found in the universe!)

• Through the process of outgassing, the outpouring of gases from the earth's interior, many other gases were injected into the atmosphere. These include:

  • water vapor (produced rain - rivers, lakes, oceans)

  • carbon dioxide

  • nitrogen

• As outgassing occurred over a period of millions of years, the atmosphere evolved to its current state