1) DISCUSS THE CHANGING COMPOSITION OF EARTH'S ATMOSPHERE THROUGH 4.6 BILLION YEARS OF HISTORY IN DETAILS PLEASE.

2) DISCUSS THE ORIGIN, CONCENTRATION AND IMPORTANCE OF MOLECULAR OXYGEN IN EARTH'S ATMOSPHERE IN DETAILS PLEASE.

 

DISCUSS THE CHANGING COMPOSITION OF EARTH'S ATMOSPHERE THROUGH 4.6 BILLION YEARS OF HISTORY 

As Earth came from a hot mixture of gas and solids 4.6 billion years ago, there was almost no atmosphere. . It had molten surface. As Earth cooled, it was primarily gasses spread by volcanoes that created the atmosphere. It contained sulfides of hydrogen, methane, and 10 to 200 times more carbon dioxide than the present atmosphere. The crust of Earth cooled and solidified allowing water to settle on it after nearly half a billion years.

The Earth was created around 4.5 billion years ago, scientists say. Possibly its early atmosphere was formed by volcanic gasses. The first billions of years of the Earth's history was thought to have been violent volcanic activity. Quite possibly, the early atmosphere was carbon dioxide plus or without oxygen. Water vapor, ammonia and methane were less common. Most of the vapor of water dispersed and created the oceans as the world cooled down. Today the Mars and Venus atmosphere is considered to be similar to that of the early world, which mainly includes carbon dioxide.

The atmosphere early cannot be understood to science and can derive evidence of it only from other sources. Volcanoes, for instance, emit high carbon dioxide concentrations. Iron-based compounds are found in very old rocks and could only have grown if little to no oxygen was present at the time.

Dependent on photosynthesis by plants, the proportion of oxygen increased.

The carbon dioxide level has reduced because:

• Sedimentary rocks (like calcareous rocks) and fossil fuels were locked.
• Plants for photosynthesis have been consumed
• It was in oceans dissolved
• The combustion of fossil fuels adds atmospheric carbon dioxide more rapidly than can be eliminated.
• The carbon dioxide levels are also rising in the atmosphere.

The atmosphere was presumably composed of hydrogen, helium, and other hydrogen-containing gases when the planet was first formed. However the aura was not long as it blew away by the sun's solar wind. Solar wind is an electrical, proton, or alpha particle flux of charged particles. Now we have an earth-rounding magnetic field that defends us from solar wind. After 4.billion years ago, the second atmosphere (mya) was formed and created by volcanic exhaustion. The release of gas that has been contained in other material is exhaust gas. In this situation, volcanic exhaust emissions released heat gasses intensely trapped within the earth. Water vapor, carbon dioxide, nitrogen, ammonia, and the like of today's volcanic gases were ejected.

The planet steadily cooled down over a long period, millions of years. As the temperature decreased enough the vapor of the water dissolved and the gas became liquid. Clouds were developed. The oceans formed from these clouds and the oceans consumed most of the atmosphere's carbon dioxide. Photolysis of carbon dioxide and water vapor by ultraviolet radiation provided a small amount of oxygen.

The climate has evolved significantly since the Planet was created more than 4 billion years ago. A broad range of geochemical and environmental (fossil) data suggests a dramatic rise in oxygen levels around 2 billion years ago. This data also suggest that the amount of carbon dioxide in the earth's past has risen dramatically, making it possible for the Earth to exist at a habitable temperature although the sun production was much smaller (approximately 25%) than today to solve the so-called 'Faint Young Sun Paradox.' The planet steadily cooled down over a long period, millions of years. As the temperature decreased enough the vapor of the water dissolved and the gas become liquid. Clouds were developed. The oceans formed from these clouds and the oceans consumed most of the atmosphere's carbon dioxide. Photolysis of carbon dioxide and water vapor by ultra-violet radiation provided a small amount of oxygen.

Continents and oceans, surrounded by an atmosphere rich in oxygen, support familial forms of life. Yet this persistence is an illusion created by the time's human experience. The Earth and its environment are constantly changing. Tectonic plates change continents, mount mountains and move the seabed, whereas processes that are not fully understood alter the climate.

Since its inception around 4.5 billion years ago, Earth has been characterized by such constant change. The evolution of this planet was shaped by heat and gravity from the beginning. The global effects of the emergence of life have gradually united these forces. The only way to grasp the origin of life and perhaps the future, is through exploring this past.

The rapid gravitational collapse of the dust cloud, which creates an extensive orb, has created scientists who believed rocky planets such as earth, mercury, venus, and marches. This view was changed in the 1960s by the space program Apollo. Moon crater surveys revealed that the impact of objects which abundantly occurred about 4.5 billion years ago caused these gouges. The number of impacts then seemed to decrease rapidly. This remark rejuvenated Otto Schmidt's theory of accretion. In 1944, in the name of Russian geophysicist, planets were growing in size, gradually.

According to Schmidt, cosmic dust lumped into a particle shape, particles became gravel, gravel became small balls, then big balls, then small planets or planetesimals. The number of planetesimals decreased as they grew. Consequently, there has been a reduction in the number of impacts between planetesimals or meteorites. Fewer accessible items meant that building a large planet took a long time. A calculation by the Washington Carnegie institution, George W. Wetherill, suggests that an object measuring 10 kilometers in diameter could spend some 100 million years building up an object of Earth's size.

The accretion process had major thermal consequences for the earth, which strongly guided its development. Big bodies slammed on the planet produced enormous heat inside and the cosmic dust that was found there melted. This furnace was active over millions of years and produces volcanic eruptions and rises up to 200 to 400 kilometers underground, which was called a magma ocean. The warming of surface from inside earth, caused by volcanism and lava ows, was intensified when enormous objects, some of them perhaps of moon size or even Mars, were continually bombarded. During this period, no life was possible.

Apollo, in addition to the clarification that Earth was created by accretion, has pushed scientists to attempt to recreate the early Earth's corresponding temporal and physical growth. The founders of geology, including Charles Lyell, who was attributed the following phrase, considered this undertaking to be impossible: no remnants of a beginning, no prospect of an end. This statement refers to the idea of not being able to recreate the young Earth because it has destroyed its remnants by its very activities. But it had been obsolete because of the developments of isotope geology in the 1960s. They began applying this technique to understanding the evolution of this Earth in the red imaginings of Apollo and the Moon Landings.

DISCUSS THE ORIGIN, CONCENTRATION AND IMPORTANCE OF MOLECULAR OXYGEN IN EARTH'S ATMOSPHERE 

Small species or blue-green algae, known as cyanobacteria. This microbes are photosynthesis: they generate carbohydrates and, yes, oxygen using sunlight, water and carbon dioxide. Currently, the photosynthesis of each plant on earth has involved symbiotic cyanobactéria (called chloroplasts) up to the present day. During the Archean Eon, more primitive microbes existed in the old way for countless eons until the creation of these cyanobacteria: anaerobically. In the absence of oxygen, the ancient species and their "extremophile" descendants today dependent on sulfate to fulfill their energy requirements

However the sulfur isotopic ratio transformed about 2,45 billion years ago, suggesting that according to a 2000 paper in Chemistry, oxygen becomes a major part of the earth's environment for the first time. At about the same time (and eons later), oxidized iron started occurring in ancient soils and iron bands were deposited on the sea.

The energy-producing chemism that powers the metabolism of most living organisms plays a vital role in the breathing. We humans require oxygen in the air we breathe to remain alive like all other species. Plants and several forms of microbes produce oxygen during photosynthesis. Both plants use and contain oxygen (within breathing) (via photosynthesis). Oxygen also can form a 3-atom molecule called ozone (O3). Ozone plays a beneficial role in Earth's stratosphere by absorbing most destructive UV radiation from the Sun while ozone is dangerous in the troposphere.

Oxygen is an atomic number 8 chemical element (it has eight protons in its nucleus). Oxygen constitutes a chemical compound (O2) of two atoms which at normal temperatures and pressures, is a colorless gas. Oxygen atoms are highly reactive to certain different chemical compounds, including water (H2O), carbon dioxide (CO2), CO2, sulfur oxides (SO2) and nitrogen oxides are integrated into them (NO and NO2). Oxygen is about 21% of Earth's climate. However that was not always the case. The earth had virtually no oxygen early in the history of our world. The by-products of microbes producing your food are photosynthesis. The photosynthetic oxygen gradually develops into the atmosphere, altering the climate and life cycle of our planet dramatically.

By composition, dry air is 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide and minor concentrations of other gases.[8] The air also incorporates variable water vapor, averaging around 1% at sea level as well as 0.4% ambient level. The structure, temperature and air pressure of air are different in altitude and only in the Earth's troposphere and artificial atmospheres can the air ideal for use in photosynthesis by terrestrial plants and the breathing of terrestrial animals. Since its conception, the Earth's atmosphere has evolved tremendously as a hydrogen atmosphere. It changed drastically at certain periods for instance, the 2.4 billion years ago Grand Oxidation Event, which raised oxygen significantly in the atmosphere, from virtually no oxygen to today's amounts. Humans have also contributed to major air pollution increases especially after industrialization, resulting in rapid changes to the atmosphere, such as ozone .

The atmosphere weighs roughly 5.15 pounds per 1018 kg[9], and the three quarters are about 11 km (6.8 pounds; 36 000 pounds) away from the earth. With a rising altitude and no clear limit between the earth and outer space, the atmosphere gets thinner and thinner. The Karmán line is also seen as the boundary between the atmosphere and outer space at 100 km (62 mi), or 1.57% of radius of the Earth. Atmospheric impacts are visible as the spacecraft re enters at an altitude of about 120 km (75 mi). Due to features like temperature and structure, multiple layers in the atmosphere can be separated.