The Tenth Planet of malevolent cyborgs that became a recurring adversary in later "Doctor Who" stories. The "tenth planet" in the title makes reference to a fictional lost planet in Earth's Solar System; at the time of production, the Solar System was generally held to consist of nine planets, prior to the redesignation of Pluto as a minor planet. "The Tenth Planet" is an incomplete "Doctor Who" serial – one of many serials that were affected by the BBC's policy of wiping archived programmes in the 1960s and 70s. Only three of the four episodes are currently held in the BBC archives; the
Emanuel Swedenborg well as spirits from planets beyond the solar system. From the 'encounters', he concluded that the planets of our solar system are inhabited and that such an enormous undertaking as the universe could not have been created for just one race on a planet or one 'Heaven' derived from its properties per planet. Many Heavenly societies were also needed to increase the perfection of the angelic Heavens and Heaven to fill in deficiencies and gaps in other societies. He argued: "What would this be to God, Who is infinite, and to whom a thousand or tens of thousands of planets,