In about one billion years, the Earth’s atmosphere will be almost completely deprived of oxygen and enriched with methane, planetary scientists said.
«One of the indicators of extraterrestrial life is the oxygen-rich atmosphere, which suggests the presence of plants and photosynthesis. The modern atmosphere of the Earth with a high oxygen content is a distinctive feature of its biosphere, but the duration of its existence is unknown, especially in the distant future,» the authors of the study say.
Planetary scientists assume that the detection of oxygen in the Earth’s atmosphere is possible only for 20-30% of the time of its entire history and, if this is true for other potentially habitable worlds, then we need to rely on additional biosignatures in the search for extraterrestrial life.