Sentence:  In spite of this , the very large radio reflectors and improved amplifying techniques which are now becoming available should make it possible to observe the radio emission of most of the <WSD>planets</WSD> in a few years . 
Meaning of the word marked with <WSD> tags:  (astronomy) any of the nine large celestial bodies in the solar system that revolve around the sun and shine by reflected light; Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto in order of their proximity to the sun; viewed from the constellation Hercules, all the planets rotate around the sun in a counterclockwise direction