Do aliens exist? Only if their planets have oceans

 
Sarah Spickernell
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In search of an ocean: no dry planets for aliens (Source: Reuters)
There's one thing we definitely have in common with aliens, if they exist, and that's a need to be near the sea.
By creating a computer simulated pattern of ocean movement on a model of a planet much like Earth, scientists at the University of East Anglia were able to study how the presence or absence of an ocean affected heat rotation.
Published in Astrobiology, the study concludes that for a planet to sustain a stable temperature, and therefore life, an ocean has to be present.
“Oceans have an immense capacity to control climate. They are beneficial because they cause the surface temperature to respond very slowly to seasonal changes in solar heating. And they help ensure that temperature swings across a planet are kept to tolerable levels,” says Professor David Stevens, a lead author of the study.
Scientists have been aware for a long time of the need for an atmosphere to be present to create conditions suitable for life, but until now most habitability models have neglected the importance of oceans.
“The number of planets being discovered outside our solar system is rapidly increasing. This research will help answer whether or not these planets could sustain alien life,” Stevens adds.
“We know that many planets are completely uninhabitable because they are either too close or too far from their sun. A planet’s habitable zone is based on its distance from the sun and temperatures at which it is possible for the planet to have liquid water.”
He uses Mars as an example of a planet that, although in the habitable zone, has no oceans to moderate the temperature. The result is that air temperatures there swing over a range of 100°C, making it impossible for life to survive.
“Oceans help to make a planet’s climate more stable, so factoring them into climate models is vital for knowing whether the planet could develop and sustain life. This new model will help us to understand what the climates of other planets might be like with more accurate detail than ever before,” he concludes.

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