The primordial atmosphere
More than 4.5 billion years ago, the Earth was formed from a cosmic cloud of gas and dust. The primordial atmosphere was formed from hydrogen and helium. It contained no oxygen.
However, the primordial atmosphere did not last long – in geological terms. Since hydrogen and helium are the lightest of all chemical elements, they were easily blown away by the powerful solar winds. The Earth’s gravitational pull was still too weak.
Highly simplified diagram of the formation
of the solar system by the contraction of a cloud consisting mainly of hydrogen and helium.
Highly simplified diagram of the formation of the solar system through the contraction of a cloud consisting mainly of hydrogen and helium. (Source: Science et Vie, September 2011)
The young Earth was initially hot and largely viscous due to very frequent meteorite impacts. Strong volcanism allowed the most volatile components (gases) to escape from the interior of the planet.
At some point, the Earth’s gravitational pull was strong enough to hold gas components. The resulting atmosphere consisted mainly of water vapor, carbon dioxide, nitrogen, methane, ammonia and hydrogen tunisia phone number library sulfide. There was still no trace of breathable oxygen. Since the Earth was still far too hot, water was mainly in the gaseous state. Oceans could not yet form.
The earth was partially molten in early times
The earth was still partially molten in the early the 3 most important components for separation from parents days and is currently in a phase of degassing due to frequent volcanism. (Source: pixabay.com)
water in liquid state
Around 3.5 to 2.5 billion years ago, the Earth had cooled down alb directory enough for water to exist in a liquid state. Over the course of hundreds of millions of years, it slowly collected in oceans on the Earth’s surface. As rain washed the carbon dioxide and sulfur out of the atmosphere (acid rain), nitrogen was the main thing that remained in the atmosphere.
photosynthesis
The first organisms (cyanobacteria) emerged in the water. They began to carry out photosynthesis with the help of sunlight. In the process, they produced sugar from water and carbon dioxide. Oxygen was created as a “waste product” of photosynthesis.
About 2.5 billion years ago, first the oceans and later the atmosphere became enriched with oxygen. Since oxygen is very reactive, it quickly combined with other elements (oxidation). The oxygen content in the atmosphere was therefore still low.
Iron-rich and oxygen-oxidized geological layers at Hamersley Gorge in Karijini National Park, Western Australia.
Iron-containing and oxygen-oxidized geological layers at Hamersley Gorge in Karijini National Park in Western Australia. (Photo: P. Stierli)
With advanced oxidation and growing plant life, the atmosphere became further enriched with oxygen. Living things that breathed in the oxygen produced carbon dioxide when they exhaled. This was absorbed by the plants, which in turn released oxygen into the atmosphere (photosynthesis). Living things and the Earth’s atmosphere thus influenced each other and determined the development of the atmosphere.
