Researchers from the University of St. Andrews and Cornell University believe that a closer look into how Earth’s atmosphere evolved over time could help us identify which exoplanets are capable of sustaining life.
According to the research paper, published in the Astrophysical Journal, the evolution of Earth’s atmosphere may be similar to that of planets found outside our solar system.
In order to reach this conclusion, a team of researchers led by astronomer and astrobiologist from the School of Earth and Environmental Sciences at Cornell, Dr. Sarah Rugheimer, looked at different geological epochs from Earth’s history. By looking at how Earth’s atmosphere evolved over time, they managed to develop atmospheric models of different stars, bigger and smaller than our Sun.
According to the researchers, a planet’s host star is an important factor in how the exoplanet’s atmosphere develops. More so, it also established how detectable potential life forms can become.
The study focused on four epochs in Earth’s atmospheric evolution. These epochs included before and after microbes appeared on the planet (3.9 billion years ago), the first rise of oxygen (2 billion years ago), the second rise of oxygen (800 million years ago), and modern-day Earth. Researchers explained that at each of these points, oxygen, carbon dioxide, and methane were drastically different in quantity.
The findings may become the basis for a potential system that helps scientists interpret early biosignatures and signs of life on Earth-like exoplanets.
“We expect to find a myriad of exoplanets beyond even our wildest imagination,” said Dr. Rugheimer “… we can start to create a grid of models to help us understand future observations.”
The researchers also took into account cloud cover and surface features such as continents and oceans, to see how these affected the models.
Image Source: Nasa.Gov