Hubble Finds Two Exoplanets Covered in Oceans 1,000 Miles Deep, Possibly Hiding Exotic Forms of Life
TL;DR
Using data from the Hubble telescope, scientists have discovered two exoplanets, Kepler-138c and Kepler-138d, which appear to be “water worlds” with oceans potentially as deep as 1,000 miles. These planets, located 218 light-years away, are unlike any in our solar system, with low densities suggesting that they are primarily composed of water. Though they may not have surface oceans like Earth, the atmosphere on these planets could be made of steam, with high-pressure liquid water existing beneath. This breakthrough raises new questions about the habitability of exoplanets.
After reading the article, a Reddit user Tom gained more than 878 upvotes with this comment: “The ocean on earth at the deepest is around 6.5 miles, and the pressure is ridiculous. What happens at 1,000 miles deep underwater? How does water behave at that level.” Don’t forget to share your thought!
An international team using the Hubble telescope has discovered that two Earth-like planets may be primarily composed of water and covered in oceans that are 1,000 miles deep.
The planets, known as Kepler-138c and Kepler-138d, were initially identified by the now-retired Kepler telescope and have been further examined with Hubble recently.
Remarkably, these planets seem to embody some of the oceanic features depicted in James Cameron’s new Avatar film, The Way of Water.
According to a statement from NASA, the planets are described as “true ‘water worlds’.”
NASA stated: “In the 1995 film Waterworld, Earth’s polar ice caps have melted completely, causing sea levels to rise over 5 miles and cover almost all land. Astronomers have discovered a pair of planets that are true ‘water worlds,’ unlike any planets found in our solar system.”
NASA elaborated: “Slightly larger than Earth, these planets lack the density of rocky bodies. Yet, they are denser than the gas giants orbiting our Sun. The best explanation is that these exoplanets possess global oceans at least 500 times deeper than Earth’s average ocean depth, which is merely a thin layer over a rocky core.”
The water-rich planets orbit the red dwarf star Kepler-138, located 218 light-years away in the constellation Lyra. Discovered in 2014 by NASA’s Kepler Space Observatory, follow-up studies with the Spitzer and Hubble telescopes indicated that these planets are likely composed largely of water. Although the direct spectral signature of water wasn’t observed, this conclusion is based on their density, derived from their size and mass.
NASA added: “Researchers from the University of Montreal have found that two exoplanets orbiting a red dwarf star are ‘water worlds,’ where a significant portion of the planets is made up of water. These worlds, found 218 light-years away in the constellation Lyra, are unlike any planet in our solar system.”
The research team, led by Caroline Piaulet from the Trottier Institute for Research on Exoplanets (iREx) at the University of Montreal, published their findings about the Kepler-138 system in Nature Astronomy.
Bjorn Benneke, a co-author and astrophysics professor at the University of Montreal, explained: “We previously believed that slightly larger planets than Earth were merely enlarged versions of Earth, composed of metal and rock, which is why we termed them super-Earths.”
He continued: “However, we have shown that Kepler-138c and d are different, with a significant portion of their volume likely consisting of water. This is the best evidence for water worlds, a type of planet theorized for a long time.”
NASA noted: “With volumes over three times that of Earth and masses twice as great, planets c and d have much lower densities than Earth. This is surprising since most slightly larger planets studied so far are rocky like Earth.”
The closest comparison would be some icy moons in the outer solar system, which are also largely composed of water surrounding a rocky core.
Piaulet said: “Imagine larger versions of Europa or Enceladus, the water-rich moons orbiting Jupiter and Saturn, but much closer to their star.”
She added: “Instead of an icy surface, they would likely have large envelopes of water vapor.”
However, the researchers cautioned that these planets may not have surface oceans like Earth’s.
Piaulet said: “The temperature in Kepler-138d’s atmosphere is likely above water’s boiling point, so we expect a thick, dense atmosphere of steam on this planet.”
She added: “Beneath this steam atmosphere, there could potentially be liquid water under high pressure, or even water in a supercritical phase.”
Benneke concluded: “As our instruments and techniques improve, allowing us to study planets farther from their stars, we may discover many more of these water worlds.”
