Planet Celesetial

Until 2006 it was the last planet of the solar system. It belongs today to the family of the dwarf planets because its characteristics are too different from those of the other planets. Pluto moves in an inclined and very elongated orbit that varies between 4.3 and 7.4 billion km from the Sun, so that for 20 years it is in front of Neptune! From so far away the Sun looks almost like a star and shines 1500 times less than on Earth! Pluto is so distant that even the light that travels very fast, at 300000 km/s, takes more than 4 hours to reach it! Pluto is half smaller than Mercury with a diameter of only 2370 km and a mass 5 times smaller than that of the Moon. Pluto is surrounded by 5 satellites. The most brilliant is Charon, which was discovered in 1978. It measures 1208 km in diameter. Given its red color, it is probably a small asteroid that was captured by Pluto. This satellite has a synchronous rotation, that is to say that it always remains in the same place in the sky relative t...

From time to time we see comets in the sky. Like asteroids, they are large, dusty, icy rocks several hundred meters long and a few kilometers in diameter. There are billions of them. They formed at the same time as the solar system but they stayed away from the Sun. There are two large reservoirs of comets: the Kuiper Belt beyond Neptune and the huge cloud of Oort that surrounds the entire solar system and is far behind Pluto. Most of the “pebbles” making up these clouds are so small and located far from the Earth that they are invisible. In time some of these small icy bodies collide or are deviated from their path. When this happens, some of these rocks may come close to the Sun. When the ice that composes them begins to melt under the heat of the Sun, we observe behind them a long bright tail: the “pebbles” becomes visible, a comet is born! Comets always have two tails: a white or slightly yellowish one consisting of dust which is often thick and slightly curved; a so-called ionic b...

As we said in the introduction, you have to prepare your observation before looking at the sky. At first it is not easy to recognize the stars and find the planets. If you want to observe the sky with the naked eye and recognize the constellations or even observe the sky with the telescope, I advise you to buy at least an atlas of the sky (book or computer program) which will explain to you in detail, with photographs and drawings, the different constellations and will describe all the objects (stars, nebulae, galaxies) that you can observe. You can also buy a mobile map of the sky or a world map that will allow you to simulate the appearance of the sky depending on where you observe, the date and time of observation. There are also computer programs. You will see, in a few weeks you will quickly recognize the main constellations and after a year you may not even need your map because you will know the sky by heart. When the night is clear and without the Moon there are at least 5000 s...