It appears that the Earth’s atmosphere could undergo a major change over a long period of time. In the beginning, our planet had predominantly methane and very low oxygen levels, which could happen even in a few billion years, as a study published by Nature Geoscience indicates.
The research that resulted in this was done by Toho University and the American space agency NASA, wow. Getting down to business, this research claims that atmospheric oxygen is apparently not permanent on Earth as usual, which may be the perfect excuse to look for life on other Earth-like planets. In this, one of the clearest possible indicators of planetary life is a detectable, oxygen-rich atmosphere, like the one Earth now has, suggesting the existence of plants and photosynthesis.
Now, of course, not everything is so simple, so to speak. It should be noted that the lifetime of these biomarkers from oxygen in the Earth’s atmosphere is uncertain, although this has something to do with the distant future.
Therefore, in the above-mentioned research, Earth systems have been modeled, which must include climate, biological and geological processes, in order to consider the time scale of the current atmospheric conditions on our planet.
The result of this appears to be that the oxygen-depleted atmosphere will last “another billion years” before rapid deoxygenation occurs similar to Earth’s before the Great Oxidation Event.
As we have said, the original atmosphere of the Earth contained very little oxygen, but that began about 2.5 billion years ago, when the level increased during the Great Oxidation Event, which marked a milestone in the history of the planet.
Why is it a big milestone in the history of the planet? Mainly because this allowed the evolution of biological forms over millions of years. Likewise, the authors of this research suggest that the detection of atmospheric oxygen on Earth is possible only during 20 or 30% of the planet’s life and consider future deoxygenation “an inevitable consequence of the increase” in fluxes from the sun.
Therefore, if the same thing happens on other planets, the study already mentioned and the stars in this message, additional bio signatures are necessary in the search for extraterrestrial life.
