Ninguno

Pluto: The Mysterious Planet.
Is the second most massive dwarf planet in our Solar System and the tenth-most-massive body observed directly orbiting the Sun. Pluto is composed primarily of rock andice and is relatively small: approximately a sixth the mass of the Earth's Moon and a third its volume. It has an eccentric and highly inclined orbit that takes it from 30 to 49 astronomical units(4.4–7.4 billion km) from the Sun. The name Pluto was proposed by Venetia Burney (1918–2009), an eleven-year-old schoolgirl in Oxford, England. The object was officially named on March 24, 1930. Pluto'sorbital period is 248 Earth years. Its orbital characteristics are substantially different from those of the planets, which follow nearly circular orbits around the Sun close to a flat reference planecalled the ecliptic. In contrast, Pluto's orbit is highly inclined relative to the ecliptic (over 17°) and highly eccentric. Despite the fact that Pluto’s orbit often crosses with that of Neptune’s,their orbits are aligned in a way that they never collide nor get too close with each other. Whenever Pluto is closest to the Sun, it also becomes the farthest above the ecliptic. This basically meansthat Pluto’s orbit passes at around 8 astronomical units above that of Neptune therefore avoiding a major collision. Pluto's rotation period, its day, is equal to 6.39 Earth days. Like Uranus, Plutorotates on its "side" on its orbital plane, with an axial tilt of 120°, and so its seasonal variation is extreme; at its solstices, one-fourth of its surface is in permanent daylight, while anotherfourth is in permanent darkness. Pluto's visual apparent magnitude averages 15.1, brightening to 13.65 at perihelion. Pluto's surface has changed between 1994 and 2002-3: the northern polar region hasbrightened and the southern hemisphere darkened. Pluto's overall redness has also increased substantially between 2000 and 2002. These rapid changes are probably related to seasonal condensation and...