The combination of oxygen and methane could reveal the presence of life on another world

In searching for life in the universe, a field known as astrobiology, scientists rely on Earth as a template for biological and evolutionary processes. This includes searching for Earth analogs, rocky planets that orbit within their parent star's habitable zone (HZ) and have atmospheres composed of nitrogen, oxygen, and carbon dioxide. However, Earth's atmosphere has evolved considerably over time from a toxic plume of nitrogen, carbon dioxide, and traces of volcanic gas. Over time, the emergenc...