Sentence:  The radio emission of a planet was first detected in 1955 , when Burke and Franklin ( 1955 ) identified the origin of interference like radio noise on their records at about 15 meters <WSD>wave</WSD> length as emission from Jupiter . 
Meaning of the word marked with <WSD> tags:  the distance (measured in the direction of propagation) between two points in the same phase in consecutive cycles of a wave