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 <WSD>records</WSD> at about 15 meters wave length as emission from Jupiter . 
Meaning of the word marked with <WSD> tags:  anything (such as a document or a phonograph record or a photograph) providing permanent evidence of or information about past events