The Doctor (Doctor Who) footage. Tom Baker did reappear, but as "the Curator", an ambiguously different character who he was not credited for playing. A voice actor, John Guilor, recorded a line of audio impersonating the First Doctor, for which he was credited as "Voice Over Artist". In other multi-Doctor stories, the multiple actors are all credited as "The Doctor", the exception being "The Three Doctors" (1972–73), which credited William Hartnell, Patrick Troughton and Jon Pertwee as "Doctor Who" as the 1972 serial preceded the practice of crediting the character as "The Doctor". In "Human Nature" (2007), the plot involves the Tenth Doctor altering
The Science of Doctor Who The Science of Doctor Who The Science of Doctor Who is a televised lecture by physicist Brian Cox discussing the nature of space and time as related to the science fiction series "Doctor Who". Cox covers topics including the nature of black holes, time dilation, time as a dimension in which to travel and the possibilities of alien life. The lecture is held at the Royal Institution's lecture hall and interspersed with small segments of Cox on the TARDIS with the Eleventh Doctor, played by Matt Smith. The lecture was released on DVD and Blu-ray on 8 September 2014 as