Ever since ancient times, celestial bodies have been a massive source of interest and mystery for humanity. Today, in astronomy, the dwarf planets are some of the most mysterious celestial bodies. This category of planets was created not so long ago. Its creation became the result of lengthy arguments between the scientists in reference to the planets of our solar system and their classification and the features that define them. Currently, apart from the eight planets in our solar system, the astronomers recognize five dwarf planets. Pluto Discovery Pluto is the most well known of the dwarf planets. The story of its discovery is very peculiar. Predicted to be out there in 1915 by Percival Lowell, Pluto was finally discovered by a self-taught astronomer called Clyde Tombaugh in Lowell Observatory by a lucky chance. In 1930 Tombaugh spend quite a very long time studying photographs of the fragments of space by means of using “blink comparator”, the device designed to compare paired photographs and detect the differences between them to find objects that moved (Beyond the Planets – the discovery of Pluto, n. d., para. 5). Such photographs show a lot of various bodies and also false objects that can be very confusing, but Tombaugh’s eyes, apparently, were very sharp, so he managed to locate Pluto. (Original photos compared by Tombaugh, n. d.). The fact that the scientist chose that particular area of the sky to examine was just a lucky accident. Initially, Pluto was recognized as the ninth planet of our solar system. Its mass and size were also considered much larger than they turned out to be later. Pluto’s temperature is one of the oldest known to science; it is minus 375 degrees F. The surface of this body is covered in gigantic craters, some of which were named after the characters of “Star Trek,” the well-known TV show about space adventures. Peculiarities Pluto is 2274 km in diameter, its density is 2.3 g/cm3, it has retrograde rotation, and its axis is tilted by 17 degrees. Pluto has always been the focus of rigorous arguments among the scientists, first of all, for a long time, it was impossible to study its features well since it is so far away. Secondly, Pluto’s orbit is very different from the orbits of the eight planets of the solar system, it has an elliptical shape, so normally Pluto is further away from the Sun than all of the planets, but there are times when its unusually shaped orbit brings it closer to the Sun than Neptune is. Finally, Pluto’s orbit is tilted in relation to the orbits of the eight planets, which all move parallel to each other. As a result of the arguments caused by this list of significant differences between Pluto and the eight planets of our solar system, the science came up with a solution to introduce a new category to distinguish between the planet-mass objects that cannot be called planets or natural satellites. The astronomers agreed to call them dwarf planets. Dwarf Planets In total, the contemporary science knows about five dwarf planets. Apart from Pluto, there are also Eris, Haumea, Makemake, and Ceres. According to their scientific definition, dwarf planets are to be of round shape and orbit the Sun directly. The difference between planet-mass objects known as planets and dwarf planets is that the latter is much smaller and cannot clear their orbits of the presence of other bodies. Dwarf planets are also known to have a smaller size than planets and their natural satellites. All of the five known dwarf planets are smaller than t