Pluto It is the smallest planet (now, of moemento, ex-planet or dwarf planet) and the one that moves farther away from the Sun.
Pluto was discovered in 1930, but it is so far that, until recently, we had little information.
Generally, Pluto was the farthest planet. But its orbit is very eccentric and, during 20 of the 249 years it takes to make it, it is closer to the Sun than Neptune.
Pluto's orbit is also the most inclined, 17º. That is why there is no danger of meeting Neptune. When the orbits intersect they do so near the ends. There's a huge vertical distance between them.
|Basic data||Pluto||The earth|
|Size: equatorial radius||1,160 km.||6,378 km.|
|Average distance to the Sun||5,913,520,000 km.||149,600,000 km.|
|Day: period of rotation on the axis||153 hours||23.93 hours|
|Year: orbit around the Sun||248.54 years||1 year|
|Average surface temperature||-230 º C *||15 º C|
|Surface gravity in the equator||0.4 m / s2||9.78 m / s2|
He made the maximum approximation in September 1989 and continued in the orbit of Neptune until March 1999. Now he moves away and will not cross this orbit again until September 2226.
In the General Assembly of the International Astronomical Union (UAI) held in Prague on August 24, 2006 a new category called plutoid was created, which includes Pluto.
Pluto has at least four small satellites and one larger, very special one: Charon. It measures 1,172 km in diameter and is less than 20,000 km from the planet. Over time, gravity has slowed its rotations and now the same face is always presented.
In fact, the rotation of this couple is unique in the Solar System. It seems that they were joined by an invisible bar and revolved around a center located in the bar, closer to Pluto, which has 7 times more mass than Charon. The Hubble telescope captured these three images that show Pluto's rotation.
Because of its density, Pluto seems made of rocks and ice. Instead, the satellite is much lighter. This difference suggests that they formed separately and then came together.
Pluto has a fine atmosphere, formed by nitrogen, methane and carbon monoxide, which freezes and falls on the surface as it moves away from the Sun.
In July 2015 the mission New horizons NASA approached Pluto. On July 13, he took photographs 768,000 kilometers from the surface. The observations made it possible to know Pluto and some of its satellites better.
Pluto's temperature can vary greatly between the point of the orbit closest to the Sun and the furthest. The difference is more than 2,500 million km.
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|Pluto and beyond||The Kuiper Belt|