When it comes to exploring exoplanets, astronauts may be wise to make sure their spacesuits are waterproof.
A new study has predicted that most habitable planets will be dominated by oceans that span over 90 per cent of their surface.
Researchers believe that the findings could provide clues to why we evolved on Earth, and not on one of the billions of other habitable worlds.
A new study has predicted that most habitable planets will be dominated by oceans that span over 90 per cent of their surface (artist's impression)
Researchers from the Institute of Cosmos Science at the University of Barcelona constructed a statistical model to predict the coverage of land and water on various exoplanets.
For a planet to have both land and water, a delicate balance must be struck between the volume of water it retains over time, and how much space it has to store it.
Both of these quantities vary substantially across the spectrum of water-bearing planets.
Until now, the reason why Earth's values are so well balanced remained an unresolved mystery.
The researchers' model predicts that most habitable planets have water that spans over 90 per cent of their surface area.
This result was reached because Earth itself is very close to being a 'waterworld' - where all land is immersed under a single ocean.
The researchers suggest that Earth's finely balanced oceans may be a consequence of the 'anthropic principle' – a theory suggesting that the universe is constrained by the necessity to allow human existence.
To create the statistical model, the researchers took feedback mechanisms into account, such as the deep water cycle, erosion and deposition.
They also used an approximation to determine the diminishing habitable land area for planets with little water, which are slowly turning into deserts.
The researchers hope their findings will help to explain why we evolved on Earth and not on another habitable planet.