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.”

Construction of FAST began in the south-western province of Guizhou in 2011, and it is situated  in a natural bowl-shaped feature that is ideal for housing the colossal concave disc. The telescope has been designed so that individual panels can be rearranged to focus on and track radio waves from specific objects of interest, which will give the dish much greater range and sensitivity than rival dishes.

O’Brien says FAST will enable more-detailed studies of pulsars: ultra-dense collapsed cores of exploding stars. “We may even find [more] pulsars outside our own galaxy,” he says. “It will also allow us to survey hydrogen in very distant galaxies, detect molecules in space, search for natural radio wave emissions from planets orbiting other stars and help in the search for radio signals from extraterrestrial civilisations.”

Zheng Xiaonian, deputy head of the National Astronomical Observation of the Chinese Academy of Sciences, says that observations will commence in September after the telescope has been thoroughly tested.

O’Brien expects that China will periodically allow astronomers from outside the country to use the telescope. “Europe’s Very Long Baseline Interferometry Network, where we link radio telescopes across continents to create a telescope with an effective diameter the size of the planet, already incorporates radio telescopes in China, and we expect FAST to take part in these observations.”

Source: New Scientist