Detecting extra solar planet from the earth is difficult. Unlike other stars, which are fuelled by nuclear reactions, extra solar planets faintly emit thermal infrared radiation. Recently, eight new extra solar planets have been discovered and it has been observed that their orbital period is longer than duration of three years (Lissauer et al 1).
These planets were “identified through observation of periodic variations of the Doppler shift of light emitted by the stars in which they are connected” (Lissauer et al 1). Some are larger than Saturn is while other even larger than Jupiter. They go round their stars closer than the other planet that goes round the solar system. Those that defy this rule travel on a high elliptical path (Scharf, 143-9). Scientific advancement will continue in the Astronomic world. This will happen as man try to improve life by discovering other habitable