World's largest telescope expected to detect primordial gravitational wave from Big Bang
Published: Nov 05, 2020 03:19 PM

Panorama photo taken on Aug. 28, 2019 shows China's Five-hundred-meter Aperture Spherical radio Telescope (FAST) under maintenance in southwest China's Guizhou Province. (Xinhua/Ou Dongqu)

China announced Wednesday that its Five-hundred-meter Aperture Spherical Telescope (FAST) - the world's largest and most powerful radio telescope - has discovered more than 240 pulsars and is expected to detect the primordial gravitational wave of the Big Bang.

FAST will also be able to help extend China's deep space exploration to the edge of the solar system, allowing the country to meet its major strategic needs. 

According to the Science and Technology Daily on Thursday, the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) said at a press conference on Wednesday that since it passed inspection and entered service in January, FAST  has been operating stably and reliably.

FAST has observed and served more than 5,200 hours since then, nearly double its expected goal, said NAOC.

FAST has discovered more than 240 pulsars, and more than 40 high-level papers have been published based on the telescope's data.

NAOC noted that FAST's research results on fast radio bursts were published in the international scientific journal "Nature" early Thursday morning.

With the improvement of its performance, the scientific potential of FAST has gradually emerged, Science and Technology Daily reported.

"The sensitivity of FAST is more than 2.5 times that of the world's second largest single-aperture radio telescope. This is the first time that a China-built radio telescope has topped the world on the important indicator of sensitivity, which is significant to promoting China's astronomy to achieve major breakthroughs," said Jiang Peng, chief engineer and executive deputy director of the FAST Operation and Development Center. 

Jiang noted that the ultra-high sensitivity makes it possible to detect gravitational waves in nanohertz and the gravitational wave at the primordial moment of the Big Bang, providing data support for the study of the physical process of the original time of the Big Bang.

Also, FAST has the ability to extend China's deep space exploration and communication capabilities to the edge of the solar system, which will allow the country to meet its major strategic needs, the media report said.

In February, nearly 100 scientists began to use and process FAST scientific data.

"In April, the telescope time allocation committee began to solicit free application projects from the domestic astronomy community. More than 170 applications have been received, with total application time of about 5,500 hours. Only 30 percent of the actual approved 1,500 hours can be supported, which shows that the competition of the FAST telescope observation time is quite fierce," said Chang Jin, member of the Chinese Academy of Sciences and director of NAOC.

FAST was completed in 2016. Its reflective surface area is equivalent in size to about 30 standard football pitches, said the report. 

Chang said FAST's new design concept created a new model for building giant telescopes, breaking through the engineering limit of a traditional fully movable radio telescope with an aperture of approximately 100 meters.

FAST's huge reflector can actively adjust its shape in real time according to the position of celestial bodies. Its 30-ton cabin moves at an altitude of 140 meters and a range of 206 meters, all with control accuracy down to the millimeter. 

FAST also faces unprecedented technical challenges due to its huge engineering volume, ultra-high precision requirements and special working methods. 

As a result, the engineering team has carried out technical research to overcome many technical problems in the fields of mechanics, measurement, control, materials, and large-scale structures.

The engineering team developed a steel cable with ultra-high fatigue resistance, which is 2.5 times higher than corresponding domestic and international standards. It also adopted an innovative two-stage adjusting mechanism composed of the world's largest span flexible parallel robot and a rigid 6-degree-of-freedom parallel robot to realize high-precision positioning.

Global Times