Terra incognita refer to the hypothesized continent Terra Australis Incognita ("The unknown land of the South"), as seen in the Theatrum Orbis Terrarum map by Abraham Ortelius (1570). During the 19th century "terra incognita" disappeared from maps of the earth, since both the coastlines and the inner parts of the continents had been fully explored. But the bottoms of the seas remain mostly un-mapped, as do many other land surfaces in the solar system. The phrase is now also used metaphorically by various researchers to describe any unexplored subject or field of research. For more history of the terms, see Terra Australis,
Another Planet / Voyager was working on one song with Swire, he decided to face his fear by travelling home and returning with his father's copy, which they then sampled for the song. One of the samples they used contained a line spoken by Burton, "...and I wandered through the weird and lurid landscape of another planet", which later gave the song its name. "Another Planet / Voyager" was the first single by Pendulum to receive widespread recognition, and as such was subject to critical attention. One review of the single describes "Voyager" as "a really well done piece of dancefloor drum and bass