A new study published in the journal Nature Astronomy revealed Astrology of naturethat there are exoplanets (outside the Earth’s solar system), which do not resemble a model the earthThere could be more rain than previously expected.
For decades, our understanding of planets, including those outside our solar system, has been based on an Earth-based model. As we know, the Earth has an iron core, surrounded by a mantle made of silicate rocks, and a surface covered with water. This simple and effective model has been the basic framework for to study exoplanets that orbit stars outside our solar system.
Silicate minerals make up about 90% of the Earth’s crustal rocks The basic unit that takes part in building all silicate minerals consists of four oxygen ions around the silicon ion tetravalent and coordinates with it, forming a tetrahedral shape.
However, recent developments in planetary science suggest that this model may be too simplistic when applied to the diverse and complex worlds outside our solar community.
The model of the Earth, with its core, mantle and clear surface, has been useful in guiding our exploration of the universe.
This model assumes that the structure of exoplanets is similar to Earth, with a metallic core, a silicate mantle, and possibly oceans or atmospheres on the surface. This hypothesis was supported by a lot of research in exoplanetary science, which helped scientists predict the formation, behavior, and possibility of life in these distant worlds.
But according to Caroline Dorn, professor of exoplanets at the Swiss Federal Institute of Technology in Zurich, “Only in recent years have we begun to understand that planets are more complex than we thought.” thinking.” This achievement has major implications for how we study and understand exoplanets, challenging the idea that Earth-like planets are the rule rather than the exception.
What happens in exoplanets?
Most of the exoplanets known today are located close to their star, meaning that they consist largely of hot worlds of molten magma oceans that have not yet cooled to form a solid shell. of silicate rock to form Earth.
Water melts well in these magma oceans, unlike carbon dioxide, which quickly escapes and rises into the atmosphere.
The iron core is located under a molten silicate shell, so how is water distributed between the silicate and iron? So the researchers in this study tried to understand that distribution with the help of model calculations based on the basic laws of physics.
The study began to investigate other planetary structures that challenge the traditional model of the Earth of its star, and it is 0.0721 astronomical units away from its star announcing its discovery in 2019.
Researchers began to study the possibility of a lot of water on that planet.
In the early stages of the planet’s evolution, much of the planet’s iron is in droplets within a hot, molten mixture called “magma soup.”
These iron droplets combine with the water in the magma, and because they are denser than the environment, they begin to descend to the core of the planet, and this process is like an elevator which water carries to the bottom.
What do larger planets have to do with the availability of water?
Previously, scientists only understood this behavior under the moderate pressure conditions found on Earth, however, the study suggests that more water tends to combine with the iron droplets on larger planets. , where internal pressures are much higher.
Under these extreme conditions, iron can absorb much more water than silicates, and due to the extreme pressure in the core, water is no longer in the normal molecular form of H2O, but it is the form of separate hydrogen and oxygen atoms.
Using the same reasoning, Carolyn Dorn says that there is much more water on Earth than previously thought, not only on the surface, but also in its depth, explaining that “the oceans that are covering our planet represents only a small part of the planet. total water conservation, and reveals that “Simulations suggest that more than 80 times the amount of water in the Earth’s oceans could be hidden deep within the planet.”
The implications of these new insights into water circulation extend far beyond Earth, affecting how scientists interpret data from exoplanet observations.
When astronomers study exoplanets, using telescopes on Earth and in space, they are sometimes able to measure the size and shape of the planet.
But if these analyzes take into account the possibility of large amounts of water being released and distributed on the planet, they could underestimate the total amount of water by as much as tenfold.
This new understanding indicates that many planets, including exoplanets, are likely to be richer in water than previously thought. As Dorn says, this achievement could significantly change our view of the frequency of water in the universe and its role in planetary evolution.
The study says that the circulation of water is also important if we want to understand how planets form and develop, because the water that has sunk into the core remains locked there forever.
However, water released into the magma ocean in the mantle can degas and rise to the surface as the mantle cools.
“So if we find water in a planet’s atmosphere, there’s probably a lot more,” Dorn explained.
Observing exoplanet atmospheres
This is what the James Webb Space Telescope, which has been sending data from space to Earth for two years, is trying to find out, because it is able to track molecules in the atmosphere exoplanets.
“Only the composition of the upper atmosphere of exoplanets can be measured directly,” Dorn says. “Our group wants to establish the connection between the atmosphere and the depth inside celestial bodies. “
The new data for the exoplanet known as TOI-270d is particularly interesting, and Dorn says: “Evidence has been collected there that there is a real interaction between the magma ocean inside it and the atmosphere.”
Her list of interesting objects she would like to study in more detail also includes the planet K2-18b, which made headlines months ago because of the possibility of life on it after the James Webb telescope to detect gaseous emissions similar to those emitted by water plankton on Earth. .
Water is one of the basic conditions for the evolution of life, and there has long been speculation about the possibility of living on large planets that contain a lot of water, that is, planets that have a mass of several times greater than the mass of the Earth and whose surface is covered by deep oceans.
Calculations then suggested that too much water could be hostile to life, arguing that a high-pressure ice cover on these watery worlds would prevent the exchange of vital substances between the ocean and the planet’s atmosphere.
The new study has now reached a different conclusion: Planets with deep layers of water are likely to be rare, since most of the water on giant planets is not found on the surface, as it was planned until now, but it is locked inside the heart.
This discovery leads scientists to hypothesize that even planets with relatively high water content may be able to develop habitable conditions similar to Earth.
