GENERAL KNOWLEDGE

Detailed explanation-1: -After loss of the hydrogen, helium and other hydrogen-containing gases from early Earth due to the Sun’s radiation, primitive Earth was devoid of an atmosphere. The first atmosphere was formed by outgassing of gases trapped in the interior of the early Earth, which still goes on today in volcanoes.

Detailed explanation-2: -Volcanic eruptions spewed gases from Earth’s interior to the atmosphere, a process called outgassing that continues today. Most of the gas was carbon dioxide and water vapor. The water vapor condensed to form part of Earth’s oceans as the surface cooled.

Detailed explanation-3: -Magma is rich in iron, and the oxidation state of iron in the rocks (essentially the chemical composition of its rust) gives scientists an indication of what the Earth’s early atmosphere was like, and how much oxygen was available at the time.

Detailed explanation-4: -Earth’s Second Atmosphere The second atmosphere, which was the first to stay with the planet, formed from volcanic outgassing and comet ices. This atmosphere had lots of water vapor, carbon dioxide, nitrogen, and methane but almost no oxygen.