Ebor

The planet Ebor was only half an hour away from Nook. (COMIC: Peril at 60 Fathoms) As seen by the Second Doctor, the people of Ebor used an explosive to move themselves nearer to the sun and improve their weather. (COMIC: The Brotherhood)

The Doctor later spoke about Ebor and their explosive in a London University lecture, even disclosing its formula and writing it on the blackboard. (COMIC: The Brotherhood)

The Second Doctor also helped a ship crew leave Nook to get to Ebor. (COMIC: Peril at 60 Fathoms)