-Galla S Kiran Kumar,Bureau Chief Telagana (Andhra Pradesh)
Are we united in this vast universe? Are there any other planets like us? This is a question that has plagued humans for centuries.
Oxygen research showed a new direction
Planets with less of this gas may also have life
The revelations of British scientists
Are we united in this vast universe? Are there any other planets like us? This is a question that has plagued humans for centuries. With the latest James Webb Space Telescope (JWST) starting its work, there is hope that an answer to this question will be found. One of the telescope’s four main goals is to study the exoplanets and determine what gases they contain. As far as we know animals need oxygen to survive. Therefore, based on the presence of this gas, a prediction can be made about the presence of life on other planets. In this background, a research carried out by the scientists of the University of Leeds in Britain on the changes in the amount of oxygen over time in the history of Pudami has become a guide for the search for extraterrestrial life.
Life, oxygen..
At present, the share of oxygen in the Earth’s atmosphere is 21 percent. But this gas has not been so abundant for a long time in the history of the planet. As it is, if we go back 45 crore years, we would have to face a situation where we could not survive without oxygen tanks on our backs. However, scientists are still not clear about the changes in the amount of oxygen over time. It is hotly debated whether this gas boosted the evolution of animals when it increased and the opposite happened when it became scarce.
The theory that is spreading..
According to the current theory, the oxygen level on Earth increased in three steps. The first of these is the ‘Great Oxidation Event’. It is believed to have happened less than 240 million years ago. Before that, there was no oxygen in the atmosphere and oceans.. With the Great Oxidation Event, this gas left a permanent mark on Earth.
* The third evolution.. happened less than 42 million years ago. This is known as the ‘Paleozoic Oxygenation Event’. Due to this, the amount of oxygen in the atmosphere has reached its present level.
* Between these two events, the Neoproterozoic Oxygenation (NOE) event took place less than 80 million years ago. That spurred the rise of oxygen.
* Some other studies have formulated that the NVO occurred before the first mammals (less than 60 million years ago).
With computer model..
Scientists at the University of Leeds have recently attempted to reconstruct atmospheric oxygen levels during the NOE period. So they wanted to know under what conditions the first generation of animals were born. For this they built a computer model of the Earth. It incorporates various processes that release or remove oxygen into the atmosphere. Searched for rocks containing carbon isotopes. Thus, the level of photosynthesis that took place in those periods was calculated. This is the process that plants use to make energy. It is the main source of oxygen on Earth.
The levels of carbon-12 and carbon-13 isotopes in the rocks were searched. Plants use most of the carbon-12 as part of photosynthesis. As a result, more carbon-13 is deposited than carbon-12 in the rocks formed in seawater and ocean beds. When those rocks are examined after billions of years, if carbon-13 is more than carbon-12 in them, it means that there was more photosynthesis at that time, and as a result, there was more oxygen in the atmosphere.
Ups and downs..
British scientists have concluded that oxygen did not increase suddenly during the Neoproterozoic period, but fluctuated very rapidly over time. According to their estimate, 75 million years ago, there was 12 percent oxygen in the atmosphere. After a few hundred thousand years it had dropped to 0.3 percent. After a few million years it increased in size again. Until the number of plants increased massively before 45 million years ago, the amount of oxygen kept increasing.. and decreasing.
The search for extraterrestrial life.
These results turned out to be very interesting. Until now, it was thought that life could have evolved because the Earth had very stable conditions throughout its 450 million year history. But if the first generation of animals had flourished in an environment where the oxygen level fluctuated greatly, scientists said that some factors might have contributed to this. It is analyzed that the period when the oxygen level in the atmosphere is low.. may have hindered the growth of complex life. It may have triggered the extinction of some primitive organisms. It is analyzed that the organisms that survived this would have expanded and diversified greatly when the amount of oxygen increased in the future. In this context, it is stated that the concept of life on planets with very low oxygen level in the atmosphere should be abandoned. It is suggested to conduct close observations in such places also.
