The study of extraterrestrial life is at an interesting stage. We look for signals from aliens and scan the stars for inconsistencies in their light that indicate the presence of hidden exoplanets. When an exoplanet is detected, we study its position in the star system to determine if it is in the habitable zone.
Gases in planets’ atmospheres block light waves, and analysing spectra can give us an idea of the planet’s chemical composition. We look for objects with life-supporting compositions similar to our own, based on our knowledge of life only on Earth.
A study by scientists from Cornell University has revealed that we may not be the most visible at the moment.
Experts analysed the last 540 million years of Earth’s evolution and its chemical ‘fingerprint’, changing every 100 million years. Despite the instability of the Earth’s atmosphere in our history (with the climate crisis worsening the situation), there are significant changes. For example, cyanobacteria began to produce energy from sunlight and release oxygen into the atmosphere, leading to fire on Earth. Previously, there was more methane due to the activities of bacteria.
