Since the 1990s, scientists have classified thousands of planets outside our solar system called exoplanets. Some of these are huge and gaseous, while others are small and rocky like our home planet. It may be denser and more watery than it used to be, and this has had a major impact on alien life.

There are four main types of exoplanets: Neptune, gas giants, super-Earths, and terrestrials. Finding these planets directly is not easy. One of the most proven methods of exoplanet hunting is called transit photometry, which basically points a telescope at a star and measures the light as the planet wobbles. A dip in brightness indicates the presence of a planet.

But two astronomers, Rafael Luque of the University of Chicago and Enric Pallé of the University of La Laguna in Spain, wanted to find the density of specific exoplanets. A closer look at some of his data for this transit showed that something was wrong.

By processing data from a directory of 34 planets, Luque and Pallé discovered that some planets contain more water than previously thought. A new analysis suggests that these planets are composed of about 50% water and 50% rock, forming a new class of exoplanets. In contrast, the Earth is almost entirely rocky, even though its surface is covered with a large amount of water, with far less than 1% of her total water. Scientists believe that water is important to life as we know it.

“It was surprising to see evidence of so many water worlds orbiting the most common type of star in the galaxy,” Luque, the paper’s lead author, said in a statement. It will have a huge impact on the search for habitable planets.” Their results were published in the journal Science.

The idea of ​​a world highly saturated with water used to be the realm of science fiction. An explorer has appeared.

To make this discovery, Luque and Pallé looked at small planets passing around red M dwarf stars. This is a very common star type in the visible universe, but it is much smaller and cooler than the Sun. When planets around M dwarfs first form, they are thought to start out as spinning disks of dust and gas. Slowly, they assume the familiar marble shape to us, but first they form a shield of hydrogen and helium called the envelope.

The envelope slowly collapses over time and eventually leaves space. Astronomers must consider these envelopes when estimating the mass and orbit of an exoplanet. However, when Luque and Pare recalculated some of these measurements, they found that these envelopes probably do not exist on some of these planets. Instead, it’s probably half rock and half water.

Want more health and science articles in your inbox? Subscribe to Salon’s weekly newsletter, The Vulgar Scientist.

However, these planets probably don’t have oceans. They are too close to the star, so surface water quickly evaporates into the supercritical gas phase. It is essentially a very hot fluid with no distinct liquid and gas phases. This will expand your radius as you swing around the sun.

“But you don’t see that in the samples,” explained Luque. “This suggests that the water does not take the form of a surface ocean.”

Instead, water is likely embedded in the rocks of these planets in equal proportions, possibly forming pockets below the surface. It is believed that the NASA hopes to send a rover to Europa in her 2024 to look for signs of extraterrestrial life.

There are probably trillions of planets in the universe. According to the Encyclopedia of Exoplanets, 5172 exoplanets have been discovered so far, occupying 3816 planetary systems. Because of their relatively small size, and because unlike stars they usually don’t produce their own light, planets are much harder to spot with telescopes than stars.

The 5172 exoplanets constitute a much smaller sample size compared to the vast number of stars observed. But it’s growing all the time, and unique discoveries about these other worlds are being published regularly. , two Earth-like exoplanets were recently discovered 105 light-years away.

Do any of these exoplanets have extraterrestrial life? So far, scientists don’t know. But tools like the James Webb Space Telescope make it easy to discover what materials exoplanets are actually made of, or at least whether they have the right materials to make life possible. will be There are many good candidates so far, but this new study could be a great addition to that growing roster.