Abigail Miri | The Monarch Ranger
Illustration of geysers on Europa, Jupiter's icy moon
Two planets were recently discovered to have a large abundance of water. While this may seem insignificant to the average person, this discovery could open up the galaxy in ways unimaginable.
Water worlds are just as they sound–planets that have a large amount of water. A prime example of this is our own planet, Earth. With roughly 70% of its surface covered in water, not to mention underground aquifers and precipitation, Earth certainly qualifies as a water world.
Another example of a water world is Europa, one of Jupiter’s moons. Underneath its ice-covered surface is an ocean of liquid water. What makes these discoveries so important?
Cross-section of Europa, one of Jupiter’s moons, displaying the water inside; Illustration Credit: NASA
One of the most important aspects of life is water. No one can live without it. This is why scientists look for signs of water when determining if a planet is capable of hosting life. Water is what keeps a planet’s climate stable and land hospitable, and also what makes it crucial for life.
Kepler-138 is a red dwarf star that is found in the constellation Lyra. It is about 219 light years away from Earth. It contains planets Kepler-138a, Kepler-138b, Kepler-138c, and newly discovered Kepler-138e.
Two of the dwarf star’s planets, Kepler-138c and Kepler-138d, were recently found to possibly have water. Both were originally thought to be rocky and dense, but new estimates suggest otherwise.
Both planets were found to be less dense than previously thought. Almost half of each planet is composed of something less dense than most rocks, but more dense than most gasses. This could be explained by the presence of water, which fits the criteria for density.
Illustration of Kepler-138d alongside Earth (published by NASA's resource gallery). Illustration credit: Benoit Gougeon (University of Montreal)
Despite the possible presence of water, both Kepler-138c and Kepler-138d are outside Kepler-138’s habitable zone, the area where life can be supported. Both are far too hot, suggesting the water in the planet is vaporous, not liquid.
However, the recently discovered fourth planet of Kepler-138, Kepler-138e, is in the habitable zone of the red dwarf star.
Presently, scientists cannot say for sure whether or not life can be supported in one of Kepler-138’s planets; but the discovery of Kepler-138e and possible discovery of water shows that life outside of Earth may not be impossible.
ACKNOWLEDGEMENTS AND LEARN MORE
To learn more about NASA’s space explorations, discoveries, and programs, click here. Learn more about the science behind natural phenomena at National Geographic.
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