Scientists have detected an atmosphere with water vapor around the exoplanet known as K2-18b. What makes the discovery so exciting is that the exoplanet is a “super-Earth” in the habitable zone of the star it orbits. This basically marks the first time that we’ve discovered water on a potentially habitable planet.
With over 4,000 exoplanets – planets that orbit stars other than ours – discovered so far it could seem like we’re on the verge of finding out if we are alone in the universe or not. Unfortunately, we don’t know much about those planets. We only know the mass and radius for most of them.
It takes a lot more than just that to understand the potential for a plane to host life. The most crucial piece of information that is generally missing is the presence, composition, and structure of the planet’s atmosphere. Signs that a planet has atmospheric water, nitrogen, and oxygen are the signs that it could support life. Atmospheric studies can teach us much about the history of a planet and investigate its habitability to determine if there are signs of life there.
The study of the atmosphere of exoplanets is still relatively limited as it takes a degree of precision that current instruments can’t deliver. With that said, we have found molecular signatures from water in gaseous planets that are similar to our own Neptune and Pluto. The discovery of water in the atmosphere of K2-18b marks the first time such conditions have been observed in a non-gaseous planet.