A new model used statistical tools to predict what the most habitable planets would look like and the results are in: It suggests that these worlds are likely to be dominated by oceans that could cover up to 90 percent of their surface.
The research, published in the Monthly Notices of the Royal Astronomical Society, was conducted by Dr Fergus Simpson of the Institute of Cosmos Sciences. For the study, he looked at the division between water and land on habitable exoplanets.
We think that water is fundamental for life to start and thrive, so a planet needs to be capable of keeping its water. This requires a good balance between all the intervening factors, characterized in the anthropic principle, with Earth-like properties the ideal ones to produce life. Based on this (maybe limited model if there are weird aliens out there), the model suggests that water worlds are most likely to be habitable.
“Based on the Earth’s ocean coverage of 71 percent, we find substantial evidence supporting the hypothesis that anthropic selection effects are at work,” Simpson said in a statement. “A scenario in which the Earth holds less water than most other habitable planets would be consistent with results from simulations, and could help explain why some planets have been found to be a bit less dense than we expected.”
The model takes into consideration water cycle, erosion, and deposition processes. This allowed Simpson to estimate the amount of habitable land depending on the size of the oceans. It turns out that the smaller the ocean, the more extended deserts would be.
We only have one example of a life-sustaining world – our own. So the expectation for where life could be hiding outside the Solar System has mostly been “planets in the habitable zone around a star.”
Simpson suggests we can do better that that: “Our understanding of the development of life may be far from complete, but it is not so dire that we must adhere to the conventional approximation that all habitable planets have an equal chance of hosting intelligent life.”