At the moment, our Earth is a paradise for life, but it will not always be like this: after a certain period of time, the composition of the atmosphere will change, and like the ancient atmosphere, methane will become dominant again, while oxygen levels will drop sharply. Fortunately, this scenario won’t materialize in the near future, but it will happen in a short time, according to a recent study published in Nature Geoscience.
Oxygen in its current form appeared in the atmosphere about 2.4 billion years ago during the so-called major oxidation event, and the Earth will return to its previous state within a few billion years. The new study also showed that the oxygen-rich atmospheres on habitable planets are only transient, and this finding is likely to affect research on life-friendly worlds as well.
The researchers developed detailed models of the Earth’s biosphere that took into account changes in the brightness of the sun as well as the associated decrease in carbon dioxide levels. This is because increasingly strong solar radiation breaks down the gas, making it lower in the atmosphere.
Reducing carbon dioxide also means that plants that perform photosynthesis will have to manage fewer resources, which will inevitably lead to a decrease in oxygen production.
Experts have previously shown that increased solar radiation will evaporate the oceans within two billion years, but recent simulations indicate that our planet will become uninhabitable in the period before that due to the very low levels of oxygen.
The drop in oxygen would be very dramatic, in practice only a millionth of a day’s level would remain in the atmosphere.” Chris Reinhard, a researcher at the Georgia Institute of Technology in in New Scientist magazine. According to the scientist, the results will also have an impact on the search for habitable planets.
Nowadays, with increasingly powerful telescopes, you can survey distant planets, all you have to do is know exactly what signals you need to look for to know if a particular planet is habitable or not. One such research program is NASA’s NexSS, in which Reinhard himself is involved. It is possible that in addition to oxygen, other vital fingerprints (signs of life) must be looked for in the planet’s atmosphere.
Not all living things depend on oxygen, for example the so-called anaerobic life forms are excellent without it. These organisms likely survived on Earth after most of the oxygen had disappeared.
full study It can be read here.
