What is the origin of the air?

The origin of the air, as we know, begins with an oxygen disaster, also known as a large oxidation that occurred about 2.7 billion years ago. Previously, the oxygen level in the air was approximately 1/50. It is a similar level of oxygen present in the atmosphere of Mars, about 1/5 percent. Like modern Mars, the atmosphere of early land was primarily carbon dioxide. The atmosphere today contains 20% oxygen and only 0.038% carbon dioxide, which makes the air thoroughly breathable for oxygen -dependent organisms like us. The oxygen disaster is clearly defined in the geological record by introducing a large amount of oxygen iron (rust). These relics are called strip iron formations. The event is called a "disaster" because oxygen is for anaerobic toxic organisms that the event has erased in large numbers. Before developing the first oxygen -producing organisms and a full -fledged oxygen disaster, there was a time delay of about 300 million years.

In the next billion years, oxyphotosynthetizing organisms flourished and produced more and more elementary oxygen. Air history, from virtually zero oxygen to 20% oxygen, has been stretched for more than two billion years. During the carbon period, about 250 million years ago, when the plants were prospering, oxygen levels were even higher than today. This allowed the existence of very large insects, including dragonfly, meganeur, with a wing of two feet. Today's air would be incomprehensible to Meganeura due to its relative lack of oxygen.

The search takes place for extraterrestrial planets with air similar to the ground, without happiness. Test -testers can determine their chemical composition, even if this body is extremely distant. This is the same technique used to determine chemical makeup distant stars.