Search for life on alien planets has been the primary aim for most planetary missions conducted by various space agencies from NASA Veritus mission to Venus to India’s Mangalyan mission to Mars and finding water is the first sign for the sustenance of all forms of life. Thanks to better instruments, scientists are finding more signs of water on more planets in the distant solar systems.
Although it’s not yet clear if exoplanets have water bodies like Earth, a recent study suggests that many of them do. However, the study also found that the water on these planets isn’t in the usual form as that on Earth.
The study, which was published in the journal Science, revealed that many exoplanets have more water than earlier thought- as much as half water and half rock. But instead of flowing in oceans or lakes, the water is actually embedded in the planet’s rocks.
“It was a surprise to see evidence for so many water worlds orbiting the most common type of star in the galaxy. It has enormous consequences for the search for habitable planets,” said Rafael Luque, a postdoctoral researcher at the University of Chicago and the first author of the study. He conducted the study with co-author Enric Pallé of the Institute of Astrophysics of the Canary Islands and the University of La Laguna.
Studying planets shadowing its star
Through the study, Luque and the other researchers looked at a group of planets around a type of star known as an M-dwarf. These are the most common stars in the galaxy and are the kind of stars that are seen around us. Over the years, scientists have discovered dozens of planets revolving around these stars. The researchers were able to identify the demographic patterns of the exoplanets by conducting a larger sample size. This allows them to analyze the data to identify trends that are hard to see in individuals.
Unfortunately, due to the brightness of the stars, we can’t see the actual planets in our galaxy. Instead, scientists can detect faint hints of the planet’s effects on the stars, such as the shadow that appears when a planet passes in front of its star. This means that it’s still not clear what these planets look like. Moreover, different approaches to discovering planets reveal different information.
Existence of water in a different form
Through the use of two different measurement techniques, the researchers were able to identify 43 planets in the Milky Way galaxy that are made up of half rock, half water, and a lighter molecule. According to Luque, water is likely to be in the subsurface pockets or rocks on these planets, similar to what’s found on Jupiter’s moon Europa.
The densities of the vast majority of the planets suggested that they’re too light to be made up of solid rock. Instead, they’re likely made up of either half rock or water. This means that instead of being the same size, these planets are likely to be made up of a lighter material.
According to Jacob Bean, an exoplanet scientist at the University of Chicago, the planets found by the researchers are generally rocky and dry. He noted that while the evidence for water bodies on these planets is interesting, more concrete proof is needed to confirm this.
The study adds to the growing body of evidence suggesting that planets outside our solar system are capable of forming and moving inward over time. This theory, which was previously dismissed, suggests that these types of planets often form farther out in their solar systems and migrate inward over time