A new study of the evolution of the Earth's atmosphere over time could provide clues to the discovery of life on exoplanets, according to researchers at St Andrews University, Scotland, and Cornell University, USA.
The new study examined in detail the evolution of the atmosphere of our planet over time and the relationship between the composition of the atmosphere and the evolution of various life forms.
Led by Dr. Sarah Rugheimer, an astronomer and astrobiologist at the University of St Andrews School of Earth and Environmental Sciences, this team has studied the different eras of our planet's geological history as part of a broader study to model the atmospheres of planets in orbits around various stars, among which there were stars larger and smaller than the Sun. The researchers found that the type of star the planet is orbiting is an important factor in the evolution of the planet's atmosphere and the availability of hypothetical signs of life on its surface for detection.
The study examined in detail the composition of the Earth's atmosphere at four different periods of its geological history: before the appearance of microorganisms (3.9 billion years ago), after the appearance of microbes and the first appearance of oxygen (2 billion years ago), during the second appearance of oxygen (800 million years ago). years ago), as well as now. At each of these periods, the contents of oxygen, methane, and carbon dioxide in the atmosphere were significantly different.
These new findings reveal the peculiarities of the evolution of life in atmospheres of various compositions and lay the foundation for the correct interpretation of the signs of life on exoplanets the size of the Earth.
The work was published in the Astrophysical Journal.