Zeta Minor
Zeta Minor was the planet farthest out in the known universe. It contained a link to a universe of anti-matter.
Characteristics
Zeta Minor had a jungle-like terrain and was home to the anti-matter creature. Professor Sorenson believed that the planet was alive and, as he told Baldwin, that it "[watched] every move they [made]." The surface was divided into sectors for the purpose of designation. (TV: Planet of Evil)
History
In the year 37166, Professor Sorenson led an expedition to Zeta Minor in search of an alternate power source that would save the Morestran civilisation.
When they found the first high quality strain, the expedition began to suffer from casualties - Lorenzo was the first - and the strain was found to have vanished. Sorenson believed the planet had "taken it back".
The Fourth Doctor and Sarah Jane Smith came to Zeta Minor in response to a distress call. (TV: Planet of Evil)