China Building World’s Largest … Radio Telescope!
The Five-hundred-metre Aperture Spherical radio Telescope (FAST), under construction in Guizhou, will dwarf the 305-metre dish at Puerto Rico’s Arecibo Observatory, currently the world’s largest. From Electronics Weekly:
“FAST is an awesome project,” says Subramaniam Ananthakrishnan of the National Centre for Radio Astrophysics in Pune, India. When completed, its 500-metre diameter single dish will make it the largest and most sensitive radio telescope in the world. What’s more, although FAST’s dish will be fixed in its crater-like setting, a series of large motors will be able to change the shape of its reflective surface, allowing it to scan large swathes of the sky. FAST will be able to peer three times further into the universe than Arecibo. Astronomers expect it to uncover thousands of new galaxies and deep-sky objects up to 7 billion light years away.
Much like the Puerto Rican landscape that is home to Arecibo, Guizhou province is pocked with dramatic karst depressions, sinkholes formed by aeons of water eating away at limestone bedrock. Using a combination of satellite imagery and aerial surveys, astronomers led by Rendong Nan of the National Astronomical Observatories (NAO) in Beijing settled on a remote 800-metre-wide karst ringed by mountains, which is far enough away from population centres to be free of radio frequency interference.
But it was not entirely unpopulated. At the bottom of the karst was a 90-year-old village of about 80 people – all members of the same family – who lived in traditional wooden homes with farm animals housed at ground level and people upstairs. Several of the children would hike out of the karst to go to a nearby school. “They would climb up every day,” says NAO astronomer Di Li. “It’s quite a climb to go over the ridge.”
Contrived though the “FAST” acronym may be, it at least breaks out of the arms-race tradition of telescope naming: the Very Large Telescope, the European Extremely Large Telescope, and the sadly cancelled Overwhelmingly Large Telescope.