The Great Oxidation Event, an important turning point in biological evolution, where oxygen is a toxic and harmful waste product!

If there is one reason why the Earth is vibrant, the atmosphere is a very important one. However, such atmospheres are not uncommon. Of the other planets in our solar system, Mars, Jupiter, Saturn, Uranus, and Neptune all have atmospheres, in addition to Mercury and the Moon.

Atmospheres are created because the gravitational force generated by the mass of the planet itself attracts molecules of gaseous matter around the planet, so the more massive the planet the greater the gravitational force and the more molecules of gaseous matter are attracted. So as opposed to Earth, Jupiter, Saturn, Uranus, and Neptune all have thick atmospheres, even atmospheres with greater mass than the central planet, which we define as a gaseous planet.

So far, life on Earth is unique, and we haven't really found any alien life. So it's not the presence of an atmosphere that makes life possible. And we know that oxygen is an essential gas for many organisms and that other planets do not have high levels of oxygen in their atmospheres. However, the same was true of the original Earth. There wasn't much oxygen in the atmosphere. And the reason for the appearance of oxygen will certainly surprise you and is known as the great oxidation event in history.

In the earliest geological ages of the Earth, there was no oxygen in the atmosphere, but some single-celled organisms had already appeared in the Earth's oceans, relying on chemical elements in the environment for energy. In the middle of the Tertiary period (the first phase of the geological era), some single-celled organisms began to absorb sunlight for energy, but this photosynthesis, unlike today, did not produce oxygen.

This anaerobic photosynthesis lasted for about a billion years until it was broken by the appearance of a cyanobacterium (also known as blue-green algae) in the late Tertiary. This cyanobacterium turned to the Earth's most abundant water resource for energy, forming what we now know as photosynthesis. Our most important oxygen is the waste product of photosynthesis.

Yes, the oxygen we can't live without was a waste at the time. And it was also harmful to other organisms at the time. Oxygen could be synthesized with many chemical elements and quickly rendered cells non-functional. If individual cells lost their cellular functions, it meant the end of life. Eventually, those organisms that cannot adapt will be eliminated.

With cyanobacterial blooms, oxygen emissions are increasing. As the planet changes, the atmosphere becomes closer to modern conditions. Unexpectedly, a life that depends on oxygen to breathe then forms. Because the atmosphere formed an ozone layer to block out ultraviolet light, it was possible to survive on land. Then the earth gradually filled with life and many people were born.

You can see this through the Great Oxidation Event. The evolution of life is so coincidental that if it hadn't been for the appearance of cyanobacteria, the Earth might have been in a state of oxygen deprivation. Of course, it is also possible that other organisms seem to have taken on the burden of changing the Earth's atmosphere, but this development was by no means inevitable. If necessary, we could easily find similar extraterrestrial organisms.

It is important to know that large oxidation events have already occurred in the oceans. The emergence and evolution of organisms is not only a condition for the occurrence of the great oxidation event but is also responsible for the Earth's unique geographical position and the avoidance of various cosmic dangers such as planetary collisions, etc.). . It is also the case that the conditions just happened to be met together to make the emergence of life possible. The evolution of life is riddled with thorns and is easily eliminated, just like those single-celled organisms that have lived for billions of years. One variable makes them extinct.

About all this, in Starlight: Alien Worlds and the Fate of Earth by Adam Frank. Adam is an astrophysicist who uses his expertise to popularise science. The content is easy to understand and free from dazzling jargon and terminology. If this interests you, pick up a copy and read it. You won't be disappointed!