China finished the world's largest single-aperture telescope

For the past 53 years, Puerto Rico's Arecibo Observatory has been the king of radio telescopes. No more. China has just finished construction of its Five hundred meter Aperture Spherical Telescope (FAST), which is 64-percent larger. That makes it the worlds largest single-aperture telescope -- the world's largest radio telescope is Russia's RATAN-600, which has a sparsely filled aperture.

Nestled in a rural area of Guizhou province, FAST was built in an isolated valley, which is important for radio telescopes, but in order to ensure there will be no magnetic disruptions, some 9,000 people are being removed from their homes and rehoused in a neighboring county. Xinhua News Agency reported displaced families are also being paid 10,000 yuan (roughly $1,500) in compensation, which translates to an average year's salary in the area.

Unlike Arecibo, which has a fixed spherical curvature, FAST is capable of forming a parabolic mirror. That will allow researchers a greater degree of flexibility. Although it's 500 meters wide, FAST effectively offers an 300-meter dish that can be pointed anywhere ±40° from the zenith, with 10 times the sensitivity of Arecibo.

FAST will begin listening to the universe this fall. It will be tasked with surveying neutral hydrogen in the milky way and other galaxies, detecting pulsars and gravitational waves and looking for signs of extra-terrestrial life.