Covering an area the size of 30 football pitches, China’s Five-hundred-meter Aperture Spherical Telescope (FAST) was officially completed this week, making it the largest radio telescope in the world.

The huge disc was assembled from 4450 individual triangular panels and dwarfs its nearest rival — the 300-metre-wide Arecibo Observatory in Puerto Rico. It should enable the detection of many astronomical objects and phenomena whose radio signals are too weak and distant to be picked up by smaller telescopes. Oh, and it will listen out for aliens.

“The size of this telescope is key to its scientific impact,” says Tim O’Brien at the University of Manchester in the UK. “The bigger the telescope, the more radio waves it collects and the fainter objects it will be able to see.”

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