The term "inner planet" should not be confused with "inferior planet", which designates those planets that are closer to the Sun than Earth is (i.e.
Ta tok delcev, ki se širi navzven s hitostjo približno 1,5 milijona kilometrov na uro, ustvarja šibko atmosfero (heliosfero), ki prežema medplanetarno snov do najmanj 100 a.e.