We often imagine that life exists on exoplanets. This is a subject that frequently crops up in science-fiction. With regard to Earth, numerous conditions had to be met in order to shelter life. Liquid water is part of the equation essential for life to exist. Therefore, using the Earth as the benchmark, the astronomers defined the notion of a habitable zone around a star where a planet could retain liquid water on its surface. This idea is based on the water phase diagram and the conditions observed on Earth, Mars and Venus.
Once you have watched this video, you will be able to define the concept of exoplanet habitability.
For more information: When talking of habitability, we often think of life as we know it, with our own existence generally serving as the point of reference. This notion was recently turned on its head with the discovery of extremophiles, organisms capable of living in conditions that would be lethal for most other organisms. This discovery opens up a new chapter in biological, technological and medical research… but also in astrobiology . The existence of extremophiles means that we have to take a fresh look at our theories on the appearance of life on Earth and its possible existence elsewhere in the Universe.
If this subject interests you, we suggest you watch the 6th video on the Astrobiology playlist (add subtitles by clicking on CC). In addition, Grenoble University, in collaboration with Ciel et Espace magazine, proposes a series of 10 podcasts on the origin of life, as part of the Origin of life project.