Sure, we tend to find planets scattered throughout this Universe quite frequently whether they are big, tiny, or not quite planets at all. That being said, whether or not any of them are livable is something we have been wondering for years and years.
Back in 2015 James Dohm and Shigenori Maruyama coined the term ‘Habitable Trinity’ when they published a paper in Geoscience Frontiers. This paper going over the elements necessary for life. While you might assume you know what these things are for most they are a little different than you’d think.
The Habitable Trinity consists of an ocean, an atmosphere, and a landmass. This landmass containing some kind of continuous material circulation system which would essentially boil down to plate tectonics. Without these things, there really isn’t any chance of life or a chance that life could become present in these places/on these planets. At least, not as we know things to be right now.
The Sun is also very important in this kind of thing, be it our Sun or a different Sun somehow. This study proposed a very interesting concept within itself. It provided us with an index for how we explore planets within this Universe.
The abstract of this study goes as follows:
Habitable Trinity is a newly proposed concept of a habitable environment. This concept indicates that the coexistence of an atmosphere (consisting largely of C and N), an ocean (H and O), and a landmass (supplier of nutrients) accompanying continuous material circulation between these three components driven by the Sun is one of the minimum requirements for life to emerge and evolve. The life body consists of C, O, H, N and other various nutrients, and therefore, the presence of water, only, is not a sufficient condition. Habitable Trinity environment must be maintained to supply necessary components for life body. Our Habitable Trinity concept can also be applied to other planets and moons such as Mars, Europa, Titan, and even exoplanets as a useful index in the quest for life-containing planetary bodies.
This could be and should be applied to the planets and exoplanets before us as mentioned in the abstract. Life is not as complicated as we make it out to be and the presence of water is without a doubt the most important factor for life in this regard. Perhaps in the future, we will find life beyond our own planet.