Without Oceans, Earth-Like Life Probably Can’t Evolve on Other Planets

It’s not all about the planet’s distance from its star, as researchers previously thought

Photo: ESA/Michael Benson/Kinetikon Pictures/Corbis

Oceans, it turns out, might be the key to Earth-like life. Not just water, but oceans. Big ones. Large bodies of water ensure that, at the planetary scale, the temperature on remains relatively stable. Without those watery expanses, weather events and hot-cold extremes would just be too much for delicate organisms such as ourselves to handle, AAP reports

Researchers from the University of East Anglia arrived at their conclusion after creating computer models of alien planets. They simulated different planetary conditions to see which would be most likely to produce life. Oceans, it turned out, were key. The result is a departure from previous findings that indicated that a planet's distance from its star could make or break its ability to support life.

The distance between a planet and its star affects the amount of heat hitting the planet, and can help determine whether any water will be a solid, liquid or gas. Oceans and atmospheres, however, can trap, redistribute or reflect the star's light. The idea that large oceans may play a very important role in making a life-friendly planet is one that's been getting a lot of support in recent years. 

Mars is a great real-world example of the power of oceans, the team explains. That planet's spot in the solar system is pretty good--not too close nor too far from the Sun. But because it has no major bodies of water, its temperature varies by more than 200 degrees, AAP points out. Mars used to be covered in giant oceans, much like Earth, but those were lost billions of years ago after the red planet lost its atmosphere to space

These findings, the team thinks, could help narrow down the search for potentially habitable exoplanets. Not only should such candidates fall within a certain distance of their star, but they should also contain a good amount of water in order to warrant further investigation.

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