Difference between planet, star and natural satellite

The first thing to keep in mind is that the bodies found in space can be very varied. You can find asteroids, comets, black holes, and so on. One of these bodies, and which is especially abundant, are the nebulae , which could be defined as immense clouds of space dust that tend to group together due to the effect of gravity.

When these nebulae are concentrated , in processes that last billions of years, they end up forming much denser bodies that, due to their high content of hydrogen and helium (two highly flammable elements of the universe), end up forming stars.. However, stars form long before they have completely absorbed the space dust that makes up nebulae, and in fact a considerable amount of this space dust will not become part of stars, but will instead be concentrated in bodies. dense that, due to the effect of gravity, will form in orbit around the star. They are the planets and, in the same way that these bodies are formed by orbiting around the star, the planets can have their own celestial bodies orbiting around them, which are natural satellites .

These structures, made up of stars, planets and natural satellites , as well as the invisible orbits that some describe in relation to others, are what are called solar systems. These solar systems are grouped in turn into groups of solar systems (or solitary stars), and form galaxies, which are the largest structures that can be seen in the universe (at least, that have been discovered until today, and which in turn are grouped into clusters of galaxies).

A star is a mass of incandescent gaseous matter that floats in space. The closest star to us is the Sun, but any star that can be observed in the universe has the same characteristics. In fact, since they are celestial bodies that are in a plasma state, they always emit light . So they are often described as celestial bodies that emit light.

On the contrary, the planets would be celestial bodies that do not emit light . However, in this case, in addition to not emitting light, they must also fulfill another important aspect, which is to orbit a star . Thus, for a planet to be considered as such, it must necessarily depend on a star. In this way, asteroids, comets or natural satellites would be left out of this definition , since, although they are celestial bodies that do not emit light, they do not have orbits related to a star .

What defines a satellite is that it is a celestial body that establishes its orbit around a planet and, what makes them natural, is that they have arisen through the normal evolution of the universe, while artificial ones are those that have been put into orbit by the hand of man. This does not make them stop being as satellites as the Moon can be, but it does mean that they are simply artificial satellites.

Natural satellites can be considered to have a relationship with their respective planet similar to that which the planet has with the star. However, the satellite has a double dependence , since it does so first of the planet and, consequently, also of the star around which the planet orbits, while the planet only depends on the star.

Another important aspect to take into account with respect to satellites is that, normally, they are created during the same process in which the formation of the solar system in question takes place. However, there may also be cases where they are the result of some kind of space catastrophe. A good example of this is our own Moon that, according to the most modern theories, arose when it detached from the Earth itself as a result of the impact of a tremendous asteroid, which launched this body of solid matter into space, where it ended up orbiting around its own planet of origin, giving rise to the natural satellite that it constitutes today.