What was the Earths atmosphere like at the beginning?
Around 4.5 billion years ago, there was no atmosphere on earth. Scientists believe that the evolution of life on Earth caused the atmosphere to change over time.
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What did scientists do to understand what the atmosphere was like?
Studied other planets and moons where there is no life. The atmospheres on these planets may be like the Earth's early atmosphere.
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Why are scientists particularly interested in volcanic activity?
Because volcanoes release large quantities of gases such as carbon dioxide, water vapour and small amounts of ammonia, methane and nitrogen.
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What is the atmosphere of Titan?
98% Nitrogen. This may have been released by volcanoes.
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Was there any oxygen on Earth?
No, there was little or no oxygen in the early atmosphere. This is known because volcanoes do not release oxygen and the iron compounds found in the Earth's oldest rocks would only form in the absence of oxygen.
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What other changes were there?
In the beginning, Earth was very hot, but it cooled down as it became older. The water vapour in the hot atmosphere also cooled down and condensed into liquid, this is how the oceans were formed.
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What happened to carbon dioxide in the atmosphere?
It was dissolved in the oceans. About half of the carbon dioxide was lost from the atmosphere in this way.
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How was sedimentary rock formed?
Some dea
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Other cards in this set
Card 2
Front
What did scientists do to understand what the atmosphere was like?
Back
Studied other planets and moons where there is no life. The atmospheres on these planets may be like the Earth's early atmosphere.
Card 3
Front
Why are scientists particularly interested in volcanic activity?
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