The Early Atmosphere

The Early Atmosphere:

By studying other planets and moons scientists hope to find out more about the Earth's early atmosphere. They think evolution of life on Earth caused its atmosphere to change

Scientists are particularly interested in volcanoes because they release large amount of gases. Volcanoes, nowadays, mainly release Carbon Dioxide and Water Vapour.

So scientists believe these gases were in the earth's early atmosphere.

The atmosphere of Titan is 98% nitrogen , which some think were released by volcanoes. They think that this could have been similar to the world's early atmosphere.

 There are also volcanoes on Mars and Venus ( their atmosphere is mainly carbon dioxide). This make's some scientists believe the earths early atmosphere was that of Carbon Dioxide

However , Titan has a icy interior. Whilst Earth , Mars and Venus have a rocky interior; This makes it more likely the earth's early atmosphere was similar to that of Mars and Venus.

There was little or no oxygen in the early atmosphere. (volcanoes do not produce oxygen and the earth's oldest rocks would only form in the absence of oxygen)

As the earth became older , it cooled down. The water vapour in the hot atmosphere also cooled down and condensed into liquid water which formed the oceans.

Key Words:

Atmosphere

Questions:

1. Name the gases thought to have been in the Earth's early atmosphere and the evidence to support this

2. How is Titan's atmosphere different to that of Mars and Venus today?

3. Why haven't the atmosphere on Mars and Venus changed for billions of years, but Earth's atmosphere has?

What you should know:

• 1.1 Know that the gases produced by volcanic activity formed the Earth’s early atmosphere.
• 1.2 Know that the early atmosphere contained:
  • a) little or no oxygen
  • b) a large amount of carbon dioxide
  • c) water vapour and small amounts of other gases.
• 1.3 Know why there are different sources of information about the development of the atmosphere which makes it difficult to be precise about the evolution of the atmosphere.
• 1.4 Be able to describe how condensation of water vapour formed oceans.