Chinese scientists have found substantial evidence for the existence of nanohertz gravitational waves. The related research was based on pulsar timing observations made with China's 500-meter Aperture Spherical Radio Telescope (FAST). Detection of nano-hertz gravitational waves necessitates a challenging process, as their frequencies are extremely low, the wave period lasts for a few years, and their wavelengths reach a few light years.
Li Kejia, a researcher at the National Astronomical Observatory of the Chinese Academy of Sciences (NAOC), who conducted the study, said, "Actually, the real gravitational wave detectors are these pulsars. "Large telescopes are used to read the signals of these pulsars, which act like a very standard clock, to learn the time and to determine how space is affected by gravitational waves."
Leveraging the high sensitivity of FAST, the China Pulsar Timing Array (CPTA) survey tracked 41 millisecond pulsars with regular cadences for 57 months. NAOC Director Chang Jin also commented that this discovery will open an important window for people to observe gravitational waves, the universe, "This will certainly lead to many great discoveries in physics."
Using nanohertz gravitational waves, researchers will be able to study supermassive objects in the universe, such as black holes, supermassive black holes, the formation, evolution and merger of galaxies, and the structure of the early universe.
Stating that the acceleration of large objects disrupts the space-time balance and produces fluctuations known as gravity, Chang said that researchers will focus more on nanohertz gravitational waves and open a new scientific direction in nanohertz gravitational wave astronomy, and the country will continue to maintain its leading position in the world in low-frequency radio astronomy.
Regional pulsar timing array collaborations, including the North American Nanohertz Gravitational Waves Observatory, the European Pulsar Timing Array, and the Australian Parkes Pulsar Timing Array, have been collecting pulsar timing data for over 20 years to detect nanohertz gravitational waves. Recently, several new regional collaborations have joined the field, including the CPTA, the India Pulsar Timing Array and the South African Pulsar Timing Array.