World’s largest radio telescope


This article was first published in the April 2016 issue of WIRED magazine. Be the first to read WIRED’s articles in print before they’re posted online, and get your hands on loads of additional content by subscribing online.

Entering the final stages of its construction, this will be the world’s largest and most sensitive radio telescope when it begins observations later this year. The Five-hundred-metre Aperture Spherical Telescope (FAST) will have a dish area of 196,000m2, enabling researchers in southwest China’s Pingtang County, Guizhou Province, where it is being built, to observe the sky with unprecedented fidelity.

“It will become the most sensitive antenna for bands below 3GHz, with the potential for major discoveries in the field of compact stars, gravitational waves, the interstellar medium, gaseous galaxies – even the origins of life,” says Di Li, the project’s deputy chief engineer.

Among the innovations is the adoption of an active, rather than passive, primary reflector. The dish is made up of reflectors that can be adjusted to account for signal deformation. This should result in a sensitivity twice that of the current largest radio telescope, the Arecibo Observatory in Puerto Rico, despite sharing a roughly equal effective dish size. Arecibo is limited to an observable area around 20° from the zenith: FAST, with its adjustable reflector, should achieve 40°.