China to accomplish construction of world's largest single-aperture radio telescope in 2016

Technicians began assembling the world's largest radio telescope, whose dish is the size of 30 football grounds, deep in the mountains of southwest China's Guizhou Province on Thursday. In the afternoon, technicians began to assemble the telescope's reflector, which is 500 meters in diameter and made up of 4,450 panels. Each panel is an equilateral triangle with a side length of 11 meters.

Once completed, the single-aperture spherical telescope called "FAST" will be the world's largest, overtaking Puerto Rico's Arecibo Observatory, which is 300 meters in diameter.
Nan Rendong, chief scientist of the FAST project with the National Astronomical Observatories, Chinese Academy of Sciences, told Xinhua that the bigger the dish is, the more capable the telescope is and the weaker messages it will receive.
"A radio telescope is like a sensitive ear, listening to tell meaningful radio messages from white noise in the universe. It is like identifying the sound of cicadas in a thunderstorm," he said.
With a perimeter of about 1.6 km, it will take about 40 minutes to walk around the telescope.
The giant dish is built upon a naturally-formed bowl-like valley in the southern part of Guizhou.
"There are three hills about 500 meters away from one another, creating a valley that is perfect to support the telescope," said Sun Caihong, chief engineer of FAST's construction, explaining the reason why this site was chosen.
The Karst formation in the local landscape is good for draining rainwater underground and protecting the reflector, Sun said.
The surrounding area has "radio silence" as there are no towns and cities within a sphere of five km and only one county center within a sphere of 25 km, he said.
The huge dish is actually hung over the ground supported by thousands of steel pillars and cables. There will be maintenance passages under it.
To overlook the whole reflector, visitors have to climb up to the top of one of the hills. A hill-top observation platform is under construction and will be open to the public, Sun said.
Not only will it be huge, the new telescope is also very sensitive.
The dish can shift to receive radio from different angles, said Zheng Yuanpeng, chief engineer of the telescope's panel project.
"Panels can change their positions through connected wires and parallel robots. We can control their position with an accuracy of 1 mm," Zheng said.
The new telescope is expected to greatly enhance Chinese scientists' capacity to observe outer space.
Wu Xiangping, director-general of Chinese Astronomical Society, said that for years Chinese scientists have worked on "second hand" data collected by others and failed to achieve breakthrough.
"Having a more sensitive telescope, we can receive weaker and more distant radio messages. It will help us to search for intelligent life outside of the galaxy and explore the origins of the universe," Wu said.
The construction of the telescope began in March 2011 and is set to finish next year.

The world's largest radio telescope, with a dish that could fit 30 football fields, is currently being assembled in the mountains of Guizhou province.
Once complete, the single-aperture spherical telescope, called FAST, will surpass the Arecibo Observatory telescope in Puerto Rico to become the biggest in the world. FAST's reflector measures 500 meters in diameter and is made up of 4,450 triangular-shaped panels with sides 11 meters long. Technicians claim that it'll be 10 times more agile than Germany's Effelsberg 100-m Radio Telescope.

The larger dish will allow the telescope to pick up weaker signals. FAST is tucked away in a bowl-like valley surrounded by hills, and with no towns or cities within a five-kilometer radius, has optimal "radio silence", according to Xinhua. So much so that experts believe the telescope may be able to detect signs of alien life.
"Having a more sensitive telescope, we can receive weaker and more distant radio messages. It will help us to search for intelligent life outside of the galaxy and explore the origins of the universe," said Wu Xiangping, director-general of the Chinese Astronomical Society.
The FAST project was introduced in 2007 and construction began in 2011. Work on the telescope's reflector just took off yesterday afternoon and it is expected to be finished by next year.