The question of whether there is life of planets other than Earth has always been prevalent in science, with scientists investigating and exploring the possibilities for the discovery of life that is sustainable on other planets within our universe.
In order to determine if a sign of life is detectable, it is necessary to identify certain bio-markers by which extra-terrestrial signs of activity can be measured. Based on what is necessary for the subsistence of life on Earth, logical bio-markers for life on Earth could be the existence of molecular oxygen (O2) and the Ozone (O3) as well as the presence of water and water vapours. This checklist is a starting point for determining signs of life however, water and CO2 existed and exist on planets before life.
Since at current it is not possible to obtain photos of all Earth-like planets within our vicinity and beyond, it is necessary to use these bio-markers as a checklist of sorts to determine whether life is present or absent on other planets. Systems of monitoring life on other planets such as a ‘Sun-Earth’ system could detect molecules by thermal emission after a week’s observation and further development on these systems could mean that in the near future, we could be examining signs of life around the universe….
As Mulder and Scully would say, ‘the truth is out there’…
About the photo: Enjoying a last sunset near Concordia research station in Antarctica. The base is located on a plateau 3200 m above sea level. A place of extremes, temperatures can drop to –80°C in the winter, with a yearly average temperature of –50°C. As Concordia lies at the very southern tip of Earth, the Sun does not rise above the horizon in the winter and does not set in the summer. The crew must live without sunlight for four months of the year. In the great open landscape covered in darkness, colours, smells and sounds are almost non-existent, adding to the sense of loneliness. The isolation and sensory deprivation can wreak havoc on crewmembers’ biological clock, making it hard to get a good night’s sleep. The base is so unlike anything found elsewhere in the world that ESA participates in the Italian-French base to research future missions to other planets, using the base as a model for extraterrestrial planets.