Li Di, the chief scientist of Both FAST and the radio division of China's National Astronomical Observatories of the China Academy of Sciences Photo: Deng Xiaoci/ GT

China is sharing its Five-hundred-meter Aperture Spherical radio Telescope (FAST) - Eye of Heaven - with the world by allocating 10 percent of its observation hours for projects run by foreign astronomers, and the percentage will definitely increase in the coming years, said FAST chief scientist.

Speaking to the Global Times during an exclusive interview, Li Di, the chief scientist of Both FAST and the radio division of China's National Astronomical Observatories of the China Academy of Sciences (CAS), revealed that astronomers from 15 countries, with scientists from the US, Europe and Australia topping the list, are using China's state-of-the-art telescope and exploring the boundaries of mankind's space knowledge. 

On March 31, 2021, the FAST officially opened to the world and started to collect observation applications from astronomers from around the world. The FAST received 7,216 hours of observation applications submitted by scientists from various countries and finally granted approval to 27 international projects. These projects started to use the FAST for scientific observations in August 2021.

The 10 percent of FAST's operation time that is open to foreign astronomers is called PI time - principal investigator time - and the scientists themselves decide where to look at and when to carry out such observations, Li explained.

Due to the ongoing COVID-19 pandemic, so far, international peers still have difficulty coming to the site for experiments and Chinese personnel at the FAST station are providing assistance to carry out their projects, Li noted. 

The FAST has witnessed continuous improvement in its operational efficiency and quality over the past two years since it was officially put into operation in January 2020. 

The annual observation time of the facility has exceeded 5,300 hours, far more efficient than international peers expected. Such efficiency is crucial to its scientific outputs.

The FAST has so far helped scientists identify about 500 new pulsars, becoming the world's most efficient facility for discovering pulsars. 

Equipped with a 19-beam receiver at L band, the FAST is so far the world's most powerful facility for searching for pulsars. Up to now, the project alone has found 279 new pulsars, including 65 millisecond pulsars and 22 pulsars in binary systems. The project found more pulsars within one and half years since its launch than the Arecibo telescope in the US did in 15 years, according to the CAS.

"The unique advantage of FAST is that it can conduct observation in the early morning and during daytime unless it encounters extreme bad weather conditions, which is different from the mainstream optical observation only available at night, and the cornerstone condition of its outstanding success," Li noted.

"The FAST has been delivering amazing outcomes, even better than what we expected when designing the facility," Li told the Global Times, while predicting that "it is safe to say it will remain the world's best radio telescope in the next decade until there is a more advanced one, the so-called Square Kilometer Array, which engendered great expectation from the science community." 

At a press conference on January 5, the CAS announced that by using the FAST, an international cooperation team led by Li and Tao-Chung Ching, has obtained for the first time high-confidence detection result of the Zeeman effect in protostellar core envelope. And the FAST served as an important observational evidence for answering the question of magnetic flux, one of the three classic questions about the formation of stars.

Also, another international team led by Li, Wang Pei and Zhu Weiwei carried out observation of FRB121102, which was the first repeating fast radio bursts (FRBs) source known to man. 

FRBs, which were first discovered in 2007, are the brightest radio bursts in the universe. The seemingly extragalactic radio pulses last only a few milliseconds. So far, scientists have detected several hundred events of FRBs, and only a few of them generate repeating bursts.

The team detected 1,652 independent bursts from FRB 121102 in about 50 days and has obtained the largest sample of FRB events to date, with its number of FRB events surpassing the total number of FRB events in all the published papers in the field.

As China is set to launch and equip Xuntian to the country's space station by 2024, Li said he believes that FAST by then would play a supportive role to the in-orbit optical observatory for Chinese scientists to carry out sky surveys.

The 2-meter-diameter Xuntian will be China's "Hubble Space Telescope," and it will even rival NASA's 31-year-old Hubble.

According to Space.com, China's Xuntian will be able to boast a field of view 300 times greater than that of Hubble while retaining a similar resolution.