With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Pluto is relatively small.
text_B: Pluto -LRB- minor-planet designation  : 134340 Pluto -RRB- is a dwarf planet in the Kuiper belt , a ring of bodies beyond Neptune .. Pluto. Pluto ( mythology ). Kuiper belt. Kuiper belt. minor-planet designation. minor-planet designation. dwarf planet. dwarf planet. bodies beyond Neptune. trans-Neptunian object. planet. planet. Neptune. Neptune. It was the first Kuiper belt object to be discovered .. Kuiper belt. Kuiper belt. Pluto was discovered by Clyde Tombaugh in 1930 and was originally considered to be the ninth planet from the Sun .. Pluto. Pluto ( mythology ). Clyde Tombaugh. Clyde Tombaugh. ninth planet. Planets beyond Neptune. planet. planet. Sun. Sun. After 1992 , its planethood was questioned following the discovery of several objects of similar size in the Kuiper belt .. Kuiper belt. Kuiper belt. In 2005 , Eris , a dwarf planet in the scattered disc which is 27 % more massive than Pluto , was discovered .. Pluto. Pluto ( mythology ). dwarf planet. dwarf planet. planet. planet. Eris. Eris ( dwarf planet ). scattered disc. scattered disc. This led the International Astronomical Union -LRB- IAU -RRB- to define the term `` planet '' formally in 2006 , during their 26th General Assembly .. planet. planet. International Astronomical Union. International Astronomical Union. That definition excluded Pluto and reclassified it as a dwarf planet .. Pluto. Pluto ( mythology ). dwarf planet. dwarf planet. planet. planet. Pluto is the largest and second-most-massive known dwarf planet in the Solar System and the ninth-largest and tenth-most-massive known object directly orbiting the Sun .. Pluto. Pluto ( mythology ). dwarf planet. dwarf planet. planet. planet. Solar System. Solar System. Sun. Sun. It is the largest known trans-Neptunian object by volume but is less massive than Eris .. Eris. Eris ( dwarf planet ). Like other Kuiper belt objects , Pluto is primarily made of ice and rock and is relatively small -- about one-sixth the mass of the Moon and one-third its volume .. Pluto. Pluto ( mythology ). Kuiper belt. Kuiper belt. Moon. Moon. It has a moderately eccentric and inclined orbit during which it ranges from 30 to 49 astronomical units or AU -LRB- 4.4 -- 7.4 billion km -RRB- from the Sun .. Sun. Sun. eccentric. orbital eccentricity. This means that Pluto periodically comes closer to the Sun than Neptune , but a stable orbital resonance with Neptune prevents them from colliding .. Pluto. Pluto ( mythology ). Sun. Sun. Neptune. Neptune. orbital resonance. orbital resonance. Light from the Sun takes about 5.5 hours to reach Pluto at its average distance -LRB- 39.5 AU -RRB- .. Pluto. Pluto ( mythology ). Moons of Pluto. Sun. Sun. Pluto has five known moons  : Charon -LRB- the largest , with a diameter just over half that of Pluto -RRB- , Styx , Nix , Kerberos , and Hydra .. Pluto. Pluto ( mythology ). five known moons. moons of Pluto. Charon. Charon ( moon ). Styx. Styx ( moon ). Nix. Nix ( moon ). Kerberos. Kerberos ( moon ). Hydra. Hydra ( moon ). Pluto and Charon are sometimes considered a binary system because the barycenter of their orbits does not lie within either body .. Pluto. Pluto ( mythology ). Charon. Charon ( moon ). binary system. binary system. barycenter. barycenter. On July 14 , 2015 , the New Horizons spacecraft became the first spacecraft to fly by Pluto .. New Horizons. New Horizons. Pluto. Pluto ( mythology ). fly by. planetary flyby. During its brief flyby , New Horizons made detailed measurements and observations of Pluto and its moons .. New Horizons. New Horizons. Pluto. Pluto ( mythology ). In September 2016 , astronomers announced that the reddish-brown cap of the north pole of Charon is composed of tholins , organic macromolecules that may be ingredients for the emergence of life , and produced from methane , nitrogen and other gases released from the atmosphere of Pluto and transferred about 19,000 km to the orbiting moon .. Pluto. Pluto ( mythology ). methane. methane. Charon. Charon ( moon ). organic. organic compound. emergence of life. Abiogenesis. nitrogen. nitrogen. atmosphere of Pluto. atmosphere of Pluto
related.