Searching for planets: direct methods

Abstract

We now turn to methods of finding planets beyond the Solar System, particularly habitable worlds. In this chapter we shall concentrate on direct methods, where we attempt to detect the radiation reflected or emitted by the planet. We could then analyse this radiation to learn about the planet and see whether it is habitable and indeed inhabited. Direct methods are very challenging, more so than indirect methods where we infer the presence of a planet from its influence either on the motion of the star it orbits, or on the quantity of radiation we receive from this star or from some background star. We learn less about a planet by indirect methods, but they currently play a very important role in our search, and are described in Chapter 10. In Chapter 11 the results of searches with the various methods are summarised.