Sentence:  Radio observations of <WSD>Venus</WSD> and Jupiter have already supplied unexpected experimental data on the physical conditions of these planets . 
Meaning of the word marked with <WSD> tags:  the second nearest planet to the sun; it is peculiar in that its rotation is slow and retrograde (in the opposite sense of the Earth and all other planets except Uranus); it is visible from Earth as an early `morning star' or an `evening star'