Beijing: As well as hunting for signals from alien life, the largest and most sensitive radio telescope ever built will search for extra-solar planets, or exoplanets, which have magnetic fields like Earth, within 100 light-years from Earth. Astronomers from countries including China and France recently published their ambitious observation plan using the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in the academic journal Research in Astronomy and Astrophysics, Xinhua news agency reported on Thursday. Li Di, a researcher at the National Astronomical Observatories of the Chinese Academy of Sciences and chief scientist of FAST, said scientists are more concerned about habitable planets, which should have not only water, a suitable temperature and atmosphere, but also a magnetic field.