Zeta Minor was the farthest planet out in the known universe. It contained a link to another universe, a universe of anti-matter. Zeta Minor's surface contained a jungle-like terrain and was home to anti-matter creatures.
In the year 37 166 the Doctor and Sarah Jane Smith responded to a distress call from Zeta Minor, a space crew landed shortly after their arrival on the planet. (DW: Planet of Evil)