earth holds key to finding life out beyond the solar system

Earth holds the key to detecting life beyond our solar system, according to new research.

Scientists from St Andrews and Cornell universities have found that the way the Earth’s atmosphere evolved over time could be vital in finding life on exoplanets.

The new study, published in the Astrophysical Journal, explains the way Earth’s atmosphere evolved corresponded to the appearance of different forms of life.

The team, led by Dr Sarah Rugheimer, astronomer and astrobiologist from the School of Earth and Environmental Sciences, studied different geological eras from Earth’s history.

The study focused on its atmosphere at four distinct points in history – before microbes (3.9 billion years ago), after microbes and the first rise of oxygen (2bn years ago), during the second rise of oxygen (800 million years ago), and Earth as it is today.

At each of these points, oxygen, methane and carbon dioxide were in drastically different abundances.

The new findings in to how life evolves in different atmospheres could lay the foundation for scientists to interpret early biosignatures and signs of life on Earth-size exoplanets.

Dr Rugheimer said: “We expect to find a myriad of exoplanets beyond even our wildest imagination.

“Even looking back at our own planet, the atmosphere has changed dramatically many times.

“By looking at the history of Earth and how different host star light would interact with a planet’s atmosphere, we can start to create a grid of models to help us understand future observations.”