Fifth planet (hypothetical) into the Sun. Unlike the Disruption Theory's fifth planet, "Planet V" is not credited with creating the asteroid belt. The concept of a fifth planet which had been destroyed to make the asteroid belt, as in the Disruption Theory, has been a popular one in fiction. Fifth planet (hypothetical) In the history of astronomy, a handful of Solar System bodies have been counted as the fifth planet from the Sun. Under the present definition of a planet, Jupiter is counted as the fifth. There are three main ideas regarding hypothetical planets between Mars and Jupiter. During the early 19th century,
The Tenth Planet The Tenth Planet The Tenth Planet is the partly missing second serial of the fourth season in the British science fiction television series "Doctor Who", which was first broadcast in four weekly parts from 8 to 29 October 1966. It was William Hartnell's last regular appearance as the First Doctor, and the first story to feature the process of regeneration, whereby the lead character, The Doctor, undergoes a transformation into a new physical form. Patrick Troughton makes his first, uncredited appearance as the Second Doctor. The serial is also notable as the first story to feature the Cybermen, a race