Pluto
(TFS) - Pluto orbits beyond the orbit of Neptune
(usually). It is much smaller than any of the official planets and now
classified as a "dwarf planet". Pluto is smaller than seven of the
solar system's moons (the Moon, Io, Europa, Ganymede, Callisto, Titan and Triton).
Planet Profile
Orbit:
5,913,520,000 km (39.5 AU) from the Sun (average)
Diameter:
2372 km
Mass:
1.303e22 kg
Until
2015 even the Hubble Space Telescope was able to resolve only the largest
features on its surface (left and above). On 14 July 2015 the New
Horizons spacecraft did a flyby of Pluto after being launched.
Pluto moons
Until
the visit by New Horizons the individual masses of Pluto and Charon could not
be determined with great accuracy.
Pluto
and Charon size comparisons by New Horizons:
Diameter
Mass Density
Pluto
2372 km 1.303e22
kg 1.860 +/- 0.013 g/cm
Charon
1208 km 1.586e21
kg 1.702 +/- 0.021 g/cm
The
Pluto-Charon pair orbit about each other around a common center of mass called
the barycenter.
Composition
Pluto
has an atmosphere consisting of mainly nitrogen extending to 1,600 km above the
surface. Methane is another constituent of the atmosphere and it is likely
caused by sunlight breaking down methane gas particles into ethylene and
acetylene, which were also discovered by New Horizons. As the ethylene and
acetylene sink into the atmosphere they condense and create a haze. In
fact two distinct layers of haze surround the planet, one starting at about 80
km above the surface and extending to 130 km, the other is lower at an altitude
of 50 km. New Horizons captured this image of the haze layers.
The
ultraviolet sunlight also acts on the haze converting it to tholins which are
dark hydrocarbons and gives Pluto its characteristic color.
Pluto has a heart shaped region called Sputnik Planum. The region is composed of nitrogen, carbon monoxide and methane ices. These ices flow like glaciers in the minus 234 C environment. The glaciers are thought to flow just as glaciers here on Earth do, although water ices on Pluto is very hard and virtually immovable.
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| Sputnik Planum |
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| Sputnik Planum |
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source: http://nineplanets.org/pluto.html
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