How is artificial oxygen created

How was our air we breathe created?

What do people and animals need to live? Food and water, of course, but above all oxygen! We get it from the air we breathe. But that was not always the case: the primordial atmosphere consisted of water vapor and poisonous gases such as carbon dioxide and foul-smelling hydrogen sulfide. We would immediately suffocate in this “air”. But what has changed since then? Why is there oxygen in the atmosphere today? And since when?

If you look back in the history of the earth, you will find traces of living things that must have needed oxygen more than two billion years ago. So there must have been oxygen in the air back then.

Petrified traces of microscopic bacteria, called blue-green algae, are much older. And they have it all: These organisms were the first to use the energy of sunlight for their metabolism. They absorbed water and carbon dioxide from their environment and, with the help of solar energy, converted them into sugar, which they used to store energy. In addition, this chemical reaction produced oxygen - as a waste product, so to speak. However, the bacteria could not do anything with the oxygen and simply released it into the environment.

At that time there was plenty of sunlight and carbon dioxide, and the world's oceans were comparatively warm. These were the best conditions for the blue-green algae to multiply and spread. In doing so, they produced more and more oxygen, which accumulated over millions of years, first in the oceans and later in the atmosphere.

The waste product of these bacteria created the conditions for higher forms of life in water and on land. From the bacteria later emerged the chloroplasts, which to this day capture the solar energy in every plant. The principle of so-called photosynthesis has also remained the same: with the help of sunlight, water and carbon dioxide are converted into sugar and oxygen. The sugar serves as a nutrient for the plant, the oxygen is released into the air and inhaled by humans and animals.


No sensible person would have thought that possible: Reinhold Messner and Peter Habeler climbed the highest mountain on earth without an oxygen device. The two extreme mountaineers arrived at the base camp yesterday, completely exhausted but happy.

Your climb to the summit of Everest begins on May 8, in the morning at half past five, after an icy night in a tent. They have been on their way up from base camp since May 6th. They are not frightened by the warnings of many doctors: They want to climb the roof of the world without artificial oxygen. A failed attempt is already behind them. Another attempt now follows from a height of almost 8,000 meters. The ascent in the thin mountain air is an ordeal, every step is torture. But both of them are in top shape and they have experience.

At noon they reach an altitude of 8,800 meters. The legs are heavy as lead, the tiredness can hardly be described. But they overcome their pain and trudge on, as if in a trance. Finally they achieve the seemingly impossible: You are standing on the summit of Everest. World record! From exhaustion, they let themselves fall into the snow. After a long break, Messner takes his camera out of his backpack and films. Back in the tent, they radio the base camp: They made it!

During the night Messner is tormented by terrible pain in his eyes: he is snow-blind. Habeler's ankle is injured. Nevertheless, the two manage to descend to base camp on May 10th. Only now do they understand their success, a feeling of triumph fills them. The sensation is perfect: Peter Habeler and Reinhold Messner have proven that Mount Everest can also be climbed without an oxygen device.

In the death zone

Doctors had warned Reinhold Messner and Peter Habeler: Moving around 8,000 meters above sea level without artificial oxygen is extremely dangerous to health. Brain cells could die and suspend controlled thinking, including the threat of unconsciousness. "You will come back as a fool," it was said briefly and drastically.

In fact, altitude sickness is not to be trifled with. From around 2,000 meters, the thinning air can make itself felt through shortness of breath, dizziness, headache or vomiting. The lungs take in less and less oxygen with increasing altitude, and the body is undersupplied. Above 7,000 meters - in the death zone - most people will pass out if they do not get extra oxygen. In the worst case, the extreme altitude leads to death. This fact has already cost many climbers their lives. The fact that Habeler and Messner climbed the summit without breathing apparatus actually borders on a miracle. It can only be explained with meticulous planning, incredible physical fitness and an iron will.

The geological ages

The earth has changed a lot since its formation: mountains, seas and continents have arisen and passed, animal and plant species have spread and become extinct. Most of these changes happened very slowly, over many millions of years. But every now and then there were decisive events: within a few thousand years the environmental conditions changed drastically.

For the scientists studying the history of the earth, these drastic changes are like a new chapter in a book: they divide the earth's history into different sections, the Eons to be named.

At the beginning, 4.5 billion years ago, the earth was completely uninhabitable. It emerged as a hot ball of glowing molten rock, surrounded by hot, caustic and poisonous gases. That sounds like a description of hell - and the name of this time comes from the Greek word "Hades" for hell: Hadaikum. It ended about four billion years ago with the first big change: The earth had cooled down so much that the surface became solid - the earth got a crust.

The earth continued to cool, so that liquid water could collect on the crust: seas were formed. And life began in these seas around 3.8 billion years ago - but initially only in the form of the simplest bacteria. The Greek word for origin or beginning is in the name of this time: Archean. An important climate change about 2.5 billion years ago marked the transition to the next epoch: primitive living things began to influence the environment. They produced oxygen that was previously almost completely absent from the atmosphere.

The early unicellular life forms became more complex over time, they formed cell nuclei. Later, some began to work together on a long-term basis in associations - this ultimately resulted in the first multicellular organisms. However, they did not yet have solid shells or skeletons, so that hardly any fossils have survived from this period. This epoch owes its name to this time before the fossils were formed: Proterozoic.

The Proterozoic ended with an explosion of life 550 million years ago: within a short period of time, the primitive forms of life developed into an enormous biodiversity. These species were built much more complex - and some already had hard shells, which were first preserved as fossils. Therefore, the history of life only becomes really visible to scientists from this point in time. And this epoch is named after the Greek term for "visible": Phanerozoic.

This age of life has lasted for 550 million years until today. However, life did not develop evenly either: after the explosive spread of life there were two devastating mass extinctions. These mark further important turning points in the history of the earth, so that scientists divide the age of life, the Phanerozoic, into three sections, Eras called, divide.

The oldest era of the Phanerozoic began 550 million years ago with the mass emergence of new species. They are called that Antiquity or Paleozoic. At first life only took place in the oceans. Then the plants colonized the land, later the animal world followed suit: first the amphibians developed, which could already feel their way a little on land, and finally also reptiles, which became independent of the water and conquered the land. The ancient world ended about 251 million years ago with the greatest mass extinction of all time: Over 90 percent of all animal and plant species died out, especially in the seas. The reason has not yet been finally clarified. Scientists suspect that an ice age was to blame, possibly as a result of a meteorite impact.

When the surviving animal and plant species had to get used to their new environment, it broke Earth Middle Ages or Mesozoic at. It is primarily the age of the dinosaurs: giant lizards evolved and ruled life for almost 200 million years. But the Middle Ages also ended with a decisive event: about 65 million years ago a large meteorite hit the earth. So much dust and ash was thrown into the air that the sky darkened and the climate changed for a long time. The dinosaurs and many other species became extinct.

Small mammals in particular benefited from this, as they were best able to adapt to climate change. They had already developed in the Mesozoic, but remained in the shadow of the dinosaurs. Now they were able to spread rapidly, conquer the most varied of habitats and keep developing. Humans also descend from this group. This most recent age continues to this day and therefore becomes the Earth New Age or Cenozoic called.

This rough classification of the earth's history is based on very drastic changes in life: explosive multiplication or mass extinction. In between, however, there were further upheavals due to various other influences - changes in the seas and continents due to continental drift, climate change between ice ages and warm periods, the composition of the air and much more. The new conditions always favored individual species and disadvantaged others. So the three sections of the Phanerozoic (Age of Life) can each be divided into several periods.

The beginnings of the earth

We would not recognize the earth immediately after its formation. It was an extremely uncomfortable planet: there were neither continents nor oceans, but a seething surface of glowing hot, viscous magma. Why couldn't the earth's crust form for a long time?

A good 4.5 billion years ago, comets, asteroids, gas and dust condensed to form our planet. Its own gravity pressed these individual parts together so that they were subjected to strong pressure. This pressure was of course highest in the earth's core, on which the weight of the entire outer layers weighed. As a result of the high pressure, the rock was heated up and melted. Outwardly, the pressure and thus also the temperature became less. Even so, the surface of the earth remained very hot for several hundred million years and could not cool down and solidify.

In order to understand the reason for this, the scientists had to look at the moon: Ancient lunar craters from the time the solar system was formed tell us that the moon was hit by numerous meteorites when it was young. It is therefore assumed that the earth was also exposed to a real rock bombardment from space at the same time. The lumps fell to the earth at high speed - and the impacts were correspondingly violent: Even lumps of a few hundred tons could easily cause an explosion the strength of an atomic bomb!

So the earth's surface continued to heat up for a long time, stirred up again and again and remained so fluid. Only when the impacts gradually subsided after a few hundred million years did the temperatures on the earth's surface drop. The rock could slowly solidify and form an earth crust that grew thicker and thicker over the course of millions of years. But to this day it is only a very thin layer that floats on a viscous, hot interior of the earth.

How did life come about?

The origin of life on earth has long been puzzled. It is known that simple bacteria developed as early as 3.8 billion years ago. But how was that possible - can life just come into being?

A student named Stanley Miller had an idea in 1953: He wanted to simulate the environmental conditions on earth in an experiment around 3.8 billion years ago. To do this, he filled a glass flask with water and some gases that were probably components of the primordial atmosphere: ammonia, methane and hydrogen. In this gas mixture he ignited electrical discharges in order to simulate the lightning bolts of the thunderstorms of that time. The water should replicate the natural water cycle. There was also a heater where the water evaporated and a cooling coil where it condensed again.

Miller ran this experiment for several days and then examined the water. In it he found a certain kind of chemical compound: amino acids, an important part of the cells of all living things. Miller had shown that the building blocks of life can be created from simple gases.

This is why scientists today assume that the gases in the primordial atmosphere also reacted to form organic substances in a similar way. Rain washed them into the sea, and high concentrations could accumulate, especially in shallow waters. Whether through aggressive sunbeams or lightning - the particles must have reacted with one another over and over again. A random combination of molecules then had a special property for the first time: It was able to reproduce itself - the beginning of life.

A shell made of gas

Seen from space, it appears like a fine bluish veil that surrounds the earth: the atmosphere. It is the envelope of air that surrounds our planet. Compared to the diameter of the earth, this shell is quite thin: if the earth were the size of an apple, the atmosphere would be about the thickness of its shell.

Without the atmosphere there would be no life on this planet, because plants, animals and humans need air to breathe. It protects us from the cold and from harmful radiation from space. It also lets meteorites burn up before they can hit the surface of the earth. This atmosphere is vital to us - but what is it actually made of?

The atmosphere is a mix of different gases. A large part of this gas mixture is nitrogen: At 78 percent, that's almost four fifths of the entire atmosphere. Only 21 percent consists of oxygen, which we need to breathe. The remaining one percent is made up of various trace gases - gases that only occur in traces in the atmosphere. These trace gases include methane, nitrogen oxides and, above all, carbon dioxide, or CO for short2 called. Although the CO2-Proportion is quite low, this trace gas has a tremendous impact on our earth's climate. This can be seen in the greenhouse effect, which is heating up our planet.

The fact that the earth has an atmosphere at all is due to gravity. It holds the gas molecules on earth and prevents them from simply flying out into space. In fact, the air becomes thinner and thinner with increasing altitude and thus decreasing gravity. Even at 2000 meters above sea level, this can become uncomfortable for people: He suffers from altitude sickness with shortness of breath, headaches and nausea. Extreme mountaineers who want to climb high peaks like the 8000m in the Himalayas therefore usually take artificial oxygen with them on their tour.

The oxygen cycle

The air we breathe contains about a fifth of oxygen. This gas is invisible, has no smell and no taste - but it is vital to us. Because we need oxygen in order to gain energy from our metabolism. Without this gas, neither humans nor most animals can survive.

Almost all of the oxygen in the air is made by plants through photosynthesis. During this process, the plant forms important nutrients from carbon dioxide and water with the help of sunlight. Oxygen is also produced as a by-product of photosynthesis.

The oxygen that the plant does not need is released into its environment. For example, a large beech tree produces about as much oxygen in one hour as 50 people need to breathe in the same time. Humans and animals breathe in this oxygen, use it up and breathe out carbon dioxide. Plants absorb this carbon dioxide during photosynthesis while at the same time generating new oxygen. A cycle is created between plants, people and animals.

In the course of the earth's history, much more oxygen has been released than living things have used to breathe. In this way, more and more oxygen was released into the atmosphere. The ozone layer, which protects us from dangerous UV radiation, could form from the increasing proportion of oxygen high up in the stratosphere.

Since people have been burning more and more oil, natural gas and coal, this natural oxygen cycle has been severely disrupted: burning consumes oxygen and at the same time carbon dioxide is also emitted. For this reason, the amount of carbon dioxide in the air has risen sharply over the past 250 years. The rise in this trace gas is the main cause of the man-made greenhouse effect and thus also of the warming of the atmosphere.