A popular misconception is to consider hot Mercury, the closest planet to the Sun, to be the smallest planet. In fact, the smallest planet is the cold and distant Pluto. Some deny him the status of a planet at all, but this is a moot point, the status of Pluto is not proven, and the non-planetary status is nothing more than a "journalistic fact." The second largest planet in size is indeed Mercury. The planet Pluto was named after the god of the underworld of the Romans, and this name should be considered quite logical. Pluto receives much less sunlight than Earth.
World of Mystery
Powerful telescopes have only been available to man in the last few decades, and the planet Pluto was officially discovered already in 1930. In 1915, it was officially announced that there was a ninth planet on the outskirts of the solar system. How was this small celestial body calculated? A body whose mass is comparable to that of the Moon inevitably exerts a gravitational influence on its neighbors. Observers noted that Uranus and Neptune deviated slightly from the calculated orbits, and this led to the existence of the most mysterious planet observed.
Under the ice
Pluto is an inhospitable planet. It is assumed that its atmosphere consists of methane gas, and the surface is covered with methane ice. The cold reigns there (usual temperature is less than 200 degrees below zero Celsius). By the way, theoretically it can collide with Neptune (their orbits overlap), but the probability of such an event is very small, the orbits of distant planets are too huge.
Two in one
However, the position of Pluto (as a separate planet) is ambiguous. The fact is that the smallest planet in the solar system has a huge satellite for its size. And the speed of rotation of Pluto around its axis coincides with the speed of rotation of Charon around it. It seemed to be frozen over one point of the planet. Therefore, if there was life on Pluto, the inhabitants of only one hemisphere would see a satellite called Charon. It is even logical to consider this pair a double planet, the red satellite is so large. Scientists believe that Charon consists of rocks. But no one can say for sure until samples of the substance are taken from the surface.
Where is the planet from?
As soon as Pluto was discovered, scientists began to guess where the smallest planet in the solar system came from. And it turned out to be the most logical to consider the baby planet as a former satellite of Neptune. It seems that Pluto itself does not contain metal rocks, like its satellite, but consists of ice. The secrets of its orbit have not yet been revealed by astronomers (as well as the secrets of some of Neptune's icy moons), but a certain similarity can be traced. But why did this happen? Perhaps Pluto was knocked out of orbit by a passing very large asteroid or comet. But where does Charon come from then? Some believe that this is a part of Pluto in the past. But this is unlikely, because the composition of the planet and the satellite is very different.
It's hard to say anything for sure about a celestial body that is so far away from us. The smallest planet in the solar system keeps its secrets. And it will keep for a very long time, mainly due to the huge distance separating it from the Earth.
In 2006, there were reports that Pluto is not a planet at all, but part of the asteroid belt. But in books and studies, Pluto is the ninth planet in the solar system. Therefore, Pluto, and not Mercury, should still have the status of the smallest planet.
