The most likely places to find alien life outside the solar system are worlds that are dominated by water. Findings of a new study have revealed that the most habitable planets are likely waterworlds with oceans that span 90 percent of their surface area.
Most Likely Composition Of A Habitable Planet
In a new study published in The Monthly Notices of the Royal Astronomical Society, Fergus Simpson, from the Institute of Cosmos Science at the University of Barcelona, and colleagues used a statistical model that can predict the most likely composition of a habitable world.
The model, which used Bayesian probability, predicted that the exoplanets that astronomers will likely find habitable to alien life are made up of oceans spanning more than 90 percent of an extraterrestrial world's surface area.
Researchers reached this conclusion because Earth itself is close to being called a waterworld, where all of the planet's land is immersed in one wide ocean.
"This scenario, in which the Earth has a much greater land area than most habitable planets, is consistent with results from numerical simulations and could help explain the apparently low-mass transition in the mass-radius relation," researchers wrote in their study.
Unique Land-Water Balance On Earth
The model hints that the unique balance of land and water on Earth is particularly unique, albeit scientists are not yet sure how or why our home planet got such a perfect balance - a balance that the model suggests is not likely to be found anywhere else.
The model takes into account the role of erosion and deposition systems as well as the deep water cycle in producing the unique balance of land and water on Earth. The work likewise suggests that planets with smaller oceans are likely to become dominated by deserts.
Simpson suggests that the reason life evolved on planet Earth and not on one of other potentially habitable worlds out there is linked to a selection effect that involves a balance of water and land.
"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," Simpson said.
Hunt For Extraterrestrial Life
Finding signs of life in other worlds is among the most common goals of space missions. NASA currently gathers data from planet Mars to find signs of life. The U.S. space agency likewise has plans to send missions to ocean worlds such as Jupiter's icy moon Europa.
The presence of water in extraterrestrial worlds is often seen as a potential hint of habitability because water is considered a critical ingredient for life. Evidence suggesting the presence of water in Europa, Ceres, and Mars has made astronomers optimistic about finding life beyond our planet.
Other factors such as temperature play as well. Earlier this week, astronomers reported of a massive Earth-like planet that they think could be possibly habitable. The exoplanet named LHS 1140b is a relatively chilly world but is considered temperate enough to support life.