It’s the World’s Largest Radio Telescope
The world’s largest radio telescope, FAST, is a massive engineering marvel. It measures 500 meters in diameter, and was built in southern Guizhou province in China. The construction took five years and $180 million to complete.
According to the researchers via state media, FAST will be searching for gravitational waves, detect radio emissions from stars and galaxies, and it will also listen for signs of intelligent extra-terrestrial life.
“The ultimate goal of FAST is to discover the laws of the development of the universe,” Qian Lei, one of the associate researchers with the National Astronomical Observatories of the Chinese Academy of Sciences, told state broadcaster CCTV.
More than 8,000 people were relocated from their homes in eight villages since the telescope needed a radio silence within a five kilometre radius. According to CCTV, during a recent test that was conducted, the telescope received radio signals from pulsar that was 1,351 light-years from Earth.
The complex project has not been without challenges — it has a radical design and initially struggled to attract staff, in part because of its remote location. But the pay-off for science will be immense. FAST will collect radio waves from an area twice the size of the next-largest single-dish telescope, the Arecibo Observatory in Puerto Rico.
The Chinese observatory’s massive size means that it can detect extremely faint radio-wave whispers from an array of sources across the Universe, such as the spinning cores of dead stars, known as pulsars, and hydrogen in distant galaxies. It will also explore a frontier in radioastronomy — using radio waves to locate exoplanets, which may harbour extraterrestrial life.
Since testing began in 2016, only Chinese scientists have been able to lead projects studying the telescope’s preliminary data. But now, observation time will be accessible to researchers from around the world, says Zhiqiang Shen, director of the Shanghai Astronomical Observatory and co-chair of the Chinese Academy of Sciences’ FAST supervisory committee.
The 1.2-billion-yuan (US$171-million) telescope, also known as Tianyan or ‘Eye of Heaven’, took half a decade to build in the remote Dawodang depression in the Guizhou province of southwest China. Its 500-metre-wide dish is made up of around 4,400 individual aluminium panels that more than 2,000 mechanical winches tilt and manoeuvre to focus on different areas of the sky. Although it sees less of the sky than some other cutting-edge radio telescopes, and has lower resolution than multidish arrays, FAST’s size makes it uniquely sensitive.
FAST examines only a tiny fraction of the sky at any one time, making it unlikely to discover many new FRBs, which are fleeting and occur in seemingly random locations. But the telescope’s “impressive sensitivity” will be useful for following up on sources in detail, says Laura Spitler, an astronomer at the Max Planck Institute for Radio Astronomy in Bonn, Germany. Repeat observations could allow scientists to learn about the environment from which an FRB emerged, and to determine whether the blasts vary in energy or recur with any set pattern.
FAST will also boost the efforts of an international collaboration that is trying to spot ripples in space-time as they sweep through the Galaxy, says McLaughlin. The International Pulsar Timing Array is using radio telescopes around the world to monitor the regular emissions from pulsars, looking for distortions that would reveal the passing of these low-frequency gravitational waves. By the 2030s, FAST should have racked up enough sensitive measurements to study individual sources of such waves, such as collisions of supermassive black holes.
