Scientists have already spotted thousands of exoplanets — planets that orbit a star outside of the Solar System — and many have the potential to harbor life.
A wild new theory suggests that exoplanets two to four times the size of Earth, known as "sub-Neptunes," are likely to be water worlds rather than gas dwarfs — and their oceans could be so deep that they almost defy comprehension.
Instead of a few kilometers deep, like Earth's oceans, Harvard researcher Li Zeng said that these alien oceans could be "hundreds or thousands of kilometers" in depth, according to Gizmodo. "Unfathomable. Bottomless. Very Deep."
The new research, published in the journal Proceedings of the National Academy of Sciences, used a complex computer model that examined data collected by the Kepler Space Telescope — NASA's exoplanet hunting device — and the Gaia mission, the European Space Agency's space telescope.
The results are astonishing: the findings indicate that some exoplanets may contain "as much as 50 percent water." That's vastly more than on Earth, where water takes up just 0.02 percent of the planet's mass. The pressure would be so dizzyingly high, in fact, that much of the water would turn to hard ice.
"It was a huge surprise to realize that there must be so many water-worlds," Zeng said in a 2018 press release.
READ MORE: Water Worlds Could Have Mind-Bogglingly Deep Oceans, New Models Suggest [Gizmodo]
More on exoplanets: New Method Could Help Astronomers Find Life-Supporting Exoplanets