Perhaps we should start with the fact that planets, like all objects in the universe, are not something purposeful, but a consequence of certain processes. So, after the Big Bang, there was a rapid expansion of space and the spread of pure energy, which in terms of temperature had a value of about 10 ^ 34. But over time, it began to spread over an increasing distance and cool down.
After that, due to fluctuations and various phenomena of particle physics, matter and antimatter began to appear in the form of elementary particles and atoms. Then they, attracted to each other, began to form foci of the first stars, which, due to their large mass, attracted more and more matter from the surrounding space. They ignited thermonuclear fusion, during which light atoms, like hydrogen, turned into increasingly heavy ones-helium, lithium, and so on.
Then the first-generation stars collapsed, throwing out their accumulated material into the already cold universe. This is how clouds of heavier elements formed, which later became protoplanetary disks.
After that, again, due to the clumping of small particles into larger ones and density fluctuations in such rings, all large bodies began to form, which acquired an increasing gravitational attraction. They began to move in their own orbit, gradually “clearing” it and increasing their mass. Eventually, a planet was formed, with solid substances forming the core and outer layers of the surface, and gases forming the atmosphere. It should be clarified that the composition of the surface and atmosphere strongly depends on temperature — depending on it, some substances can be either components of the surface or the atmosphere.
If you are asking about something “why they are needed” or “what is the point”, be sure to specify-for whom. The same phenomenon may have different meanings for different subjects. For example, for us, the planet Earth is needed to live, and for the inhabitants of Alpha Centauri, if there are any, it is needed for astrophysical experiments, for example. The subject must necessarily have free will, otherwise the question of meaning is meaningless.
Perhaps we should start with the fact that planets, like all objects in the universe, are not something purposeful, but a consequence of certain processes. So, after the Big Bang, there was a rapid expansion of space and the spread of pure energy, which in terms of temperature had a value of about 10 ^ 34. But over time, it began to spread over an increasing distance and cool down.
After that, due to fluctuations and various phenomena of particle physics, matter and antimatter began to appear in the form of elementary particles and atoms. Then they, attracted to each other, began to form foci of the first stars, which, due to their large mass, attracted more and more matter from the surrounding space. They ignited thermonuclear fusion, during which light atoms, like hydrogen, turned into increasingly heavy ones-helium, lithium, and so on.
Then the first-generation stars collapsed, throwing out their accumulated material into the already cold universe. This is how clouds of heavier elements formed, which later became protoplanetary disks.
After that, again, due to the clumping of small particles into larger ones and density fluctuations in such rings, all large bodies began to form, which acquired an increasing gravitational attraction. They began to move in their own orbit, gradually “clearing” it and increasing their mass. Eventually, a planet was formed, with solid substances forming the core and outer layers of the surface, and gases forming the atmosphere. It should be clarified that the composition of the surface and atmosphere strongly depends on temperature — depending on it, some substances can be either components of the surface or the atmosphere.
If you are asking about something “why they are needed” or “what is the point”, be sure to specify-for whom. The same phenomenon may have different meanings for different subjects. For example, for us, the planet Earth is needed to live, and for the inhabitants of Alpha Centauri, if there are any, it is needed for astrophysical experiments, for example. The subject must necessarily have free will, otherwise the question of meaning is meaningless.