| − | Pluto was initially supposed to have been a [[moon]] of [[Neptune]]. But with the discovery of [[Charon]] in 1978, and the subsequent discoveries of its other moons [[Hydra (moon)|Hydra]] and [[Nix]], that theory became far less plausible. The current theory is that Pluto and Charon both formed from the solar nebula as the other planets in the solar system did. <ref>http://www.britannica.com/eb/article-54312/Pluto</ref> | + | Pluto was initially thought to have originally been a [[moon]] of [[Neptune]] that escaped into its own orbit around the [[Sun]]. But with the discovery of [[Charon]] in 1978, and the subsequent discoveries of its other moons [[Hydra (moon)|Hydra]] and [[Nix]], that theory became far less plausible. The current theory is that Pluto and Charon both formed from the solar nebula as the other planets in the solar system did. <ref>http://www.britannica.com/eb/article-54312/Pluto</ref> |