Is there life out there? Some people like to think so. While many have been searching for alien life forms and have read on stories about finding something beyond what we know, we still need a solid proof. Still, this hasn’t stopped scientists from searching.
One good sign of life is water. Experts believe that when a planet contains water, it may also support life. Years back, only a few planets were found to have water, but in recent years, the researchers have been discovering more secrets that may show that there is actually life beyond earth.
Water is the very thing that sustains all forms of life here on Earth. In fact, the scientists have studied rain cycles as it goes to the rivers and oceans before it goes back up again. This is what allows our climate to be stable and livable. When these experts want to look for signs of life outside, the first thing they look for are planets with water. This is what goes first on their criteria.
There’s a new study made and the findings suggest that there are more planets that contain large amounts of water. The number of planets was more than they thought. These planets had as much as half water and half rock, and the water was probably embedded in rock instead of flowing as large bodies of oceans and rivers on the surface.
“It was a surprise to see evidence for so many water worlds orbiting the most common type of star in the galaxy,” said Rafael Luque. He is the first author on the new paper and a postdoctoral researcher hailing from the University of Chicago. “It has enormous consequences for the search for habitable planets,” he added.
Years back, telescopes were designed to be powerful. However, technology was limited then. Credit can be given to the better telescope instruments we have now. Because of these, scientists are discovering more signs of additional planets found in the distant solar systems. They now have a larger sample size that helped them see demographic patterns. This is somewhat akin to looking at the population of an entire town so that they can observe trends that are hard to see when these are observed individually.
Luque, along with co-author Enric Pallé of the Institute of Astrophysics of the Canary Islands and the University of La Laguna, chose to take a population-level look at a group of planets. These planets are situated around a type of star called an M-dwarf. These are considered to be the most common stars around the galaxy. At this point, the scientists have managed to catalogue dozens of planets around the area.
However, stars are so much brighter than the planets around. This means that seeing the actual planets can be challenging. So, scientists detect faint signs of the planets’ effects on their stars. This means that they look at the shadow created when a planet goes in front of the star as it circles its path. They also look for the tiny tug on a star’s motion as the planets around orbit. While many discoveries have been made, there are still questions about how these planets really look like.
“The two different ways to discover planets each give you different information,” said Pallé. So, they capture the shadow that is created when a planet crosses the star and goes in front of it. By doing this, the scientists can measure the diameter of the planet, and by doing so, they can also measure the tiny gravitational pull that a planet exerts on its star. This is then when they are able to calculate its mass.
When they combine both measurements, these scientists can get an idea of the planet’s overall makeup. It can be a large gas planet such as Jupiter, or a small, dense, rocky one like the one we live in. These analyses had been performed for each planet. What is rare is when they are able to get measurements of entire known population of such planets that are found in the Milky Way galaxy. As the team looked at the numbers of the total of 43 planets, they saw something that caught them by pleasant surprise.
The densities of a large percentage of the planets found somewhat indicated that they were too light for their size to be made up of just rock. Instead, the scientists surmised that these were probably made up of 50 percent rock and 50 percent water, or perhaps even another lighter molecule. This is very much like picking up balls made of different materials. A good example would be a bowling ball versus a basketball.
In Search of Worlds that Contain Water
It may nice to picture some of these planets like Waterworld: something that’s fully covered in deep oceans. It may seem too far-fetched because these planets are so close to their suns that any surface water would simply be in its supercritical gaseous phase, which is something that would increase their radius. “But we don’t see that in the samples,” explained Luque. “That suggests the water is not in the form of surface ocean.”
So, the scientists believe that the water might exist if this is mixed into the rock or in pockets found below the ground. Those conditions would be very much like Europa, one of Jupiter’s moons. They believe that this may have liquid water found underground.
“I was shocked when I saw this analysis—I and a lot of people in the field assumed these were all dry, rocky planets,” said UChicago exoplanet scientist Jacob Bean. Luque joined his group so that they can conduct further analyses.
The finding has published in the journal Science, and in it, they made suggestions that matched a theory of exoplanet formation that lost its popularity in the past few years. This theory suggested that many planets form farther out in their solar systems and slowly migrate inward over the ages. If this is hard to picture, just Imagine groups of rock and ice forming together in the cold conditions far from the star, and as time passes, they are slowly pulled inward because of the star’s gravity.
Though the proof gathered is quite convincing, Bean said that he and his colleagues would still like to see “smoking gun proof” that allows them to finally assume that one of these planets contain water. That’s something they hope to discover with JWST, which is NASA’s newly launched space telescope that is the poised to succeed Hubble.
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