The Dwarf Planet
Pluto was discovered in 1930 by Clyde Tombaugh and was named after the Roman God of the underworld. It is the smallest and most distant planet in our Solour System. It is made up of two layers, the core, which is made up of iron-nickel alloy and a water ice outer layer. Because Pluto is so distant from Earth, astronomers know little about its surface conditions but they can estimate that it has a diameter one fifth that of Earth. Spinning on its axis, Pluto orbits the Sun once every six Earth days. However, in 2006, the International Astronomical Union reclassified Pluto as a dwarf Planet. This video gives a further explanation as to why Pluto is no longer considered a planet.
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