Hocotate
Hocotate is Captain Olimar's home planet.
Hocotate has a thin atmosphere lacking large amounts of oxygen. The name "Hocotate" comes from Nintendo's headquarters' street address. It is near other planets, which may or may not be inhabited. It possesses 2 sets of visible rings, which are probably composed of dust and rock, like most astronomical rings. Their presence could mean that Hocotate is a very large planet, which contrasts with the small size of its people. The planet also has two moons and is somewhat barren and rocky, with few plants, but the daytime sky is so transparent that stars, galaxies, and the planet's rings and its moons can be seen during the day; possibly indicating that the atmosphere is very poor.
The people of Hocotate (the Hocotations) are about the size of a quarter and cannot breath oxygen, which is poisonous yo Hocotations, and as such, Olimar and Louie must protect themselves while on the Planet of the Pikmin by wearing a spacesuit.
The technology is very advanced, as even quarks have been utilized (seen in the Gluon Drive part in Pikmin 1). With such advanced technology, it is ironic that comparatively primitive, human-made objects are considered treasures there.
Apparently, Olimar has publicized the location of the Pikmin Planet. This can be inferred due to numerous references to "other travelers". As it is doubtful that these are Pikmin (who are unable to speak), the only possible choice is that they are people of Hocotate.
The currency of Hocotate is the Poko, a small type of coin that resembles those from the Super Mario series. Items from the Pikmin Planet are considered extremely rare treasures, and can be worth a particularly large amount of Pokos, many of which helped Olimar and Louie pay off their company's debt of 10,100 Pokos. (In comparison, 100 Pokos is more than a year's salary for the President of Hocotate Freight.)
The Hocotations speak an unknown language. It could possibly be a language spoken on Earth in either:
1.: an unaltered state
2.: spoken backwards
3.: extremely modified.
Of course, these are all assumptions, and Nintendo has not mentioned anything about its origin.