Exoplanets with oceans may be more common than previously thought

Hyperaxion Jun 20, 2020

NASA is studying the probability of exoplanets having oceans based on the conditions of the moons Enceladus and Europa.

More than 4,000 exoplanets have already been identified. How likely is one of them to have oceans? That was the question asked by NASA planetary scientist Lynnae Quick, based on her studies of Saturn’s Enceladus and Jupiter’s Europa.

Exoplanets with oceans may be more common than previously thought
Illustration of NASA’s Cassini spacecraft flying across the moon Enceladus in October 2015 (Credit: NASA / JPL-Caltech).

“Plumes of water erupt from Europa and Enceladus, so we can tell that these bodies have subsurface oceans beneath their ice shells, and they have energy that drives the plumes, which are two requirements for life as we know it,” explains Quick, who is a specialist in volcanism and ocean worlds, in a statement.

The scientist decided to explore whether planets similar to these moons exist and whether they could also be geologically active enough to shoot plumes from their surfaces that can be detected by telescopes.

To make this difficult analysis, Quick and her team selected 53 exoplanets similar in size to Earth, although they could have masses up to eight times that of our planet. The scientists assume that planets of this size are more solid than gaseous and are therefore more likely to harbor liquid water on or under their surfaces.

The study began in 2017, and since then, at least 30 planets with these same characteristics have been discovered. But they were not included in the analysis led by Lynnae Quick, published on Thursday (18) in the Publications of the Astronomical Society of the Pacific.

The team also found out how much energy each of the selected exoplanets could be generating and releasing as heat. The results showed that all the selected planets are likely to have volcanic activity on their surfaces and that 26% may be oceanic, with most of them likely to harbor seas beneath their ice shells – just like Europa and Enceladus. In addition, many of these planets could be releasing more energy than these moons.

Although the conclusions are still only hypotheses, they can help narrow the list of exoplanets with conditions favorable to life. In the next decade, NASA’s Europa Clipper spacecraft will explore the surface and subsoil of the Jupiter’s moon Europa to provide information about its subterranean environment.

The more scientists learn about Europa and other potentially habitable moons in our Solar System, the better they will be able to understand similar worlds around other stars.


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