Chinese scientists have discovered significant evidence for the existence of nanohertz gravitational waves. The relevant research was based on pulsar timing observations conducted with China’s Five-hundred-meter Aperture Spherical Telescope (FAST). Detecting nanohertz gravitational waves poses a challenging process due to their extremely low frequencies, wave periods lasting several years, and wavelengths spanning multiple light-years.
Li Kejia, a researcher from the National Astronomical Observatories of China (NAOC) of the Chinese Academy of Sciences, stated, “In fact, these pulsars are the real gravitational wave detectors. Large telescopes are used to read the signals of these pulsars, which act like very standard clocks, in order to learn about time and determine how space is affected by gravitational waves.”
Leveraging the high sensitivity of FAST, the Chinese Pulsar Timing Array (CPTA) study tracked 57 millisecond pulsars with regular cadence for 41 months. Chang Jin, the director of NAOC, emphasized that this discovery would open an important window for observing gravitational waves and commented, “This will definitely lead to many major discoveries in physics.”
By using nanohertz gravitational waves, researchers can investigate supermassive objects such as black holes, supermassive black holes, galaxy formation, evolution, mergers, and the structure of the early universe.
Chang explained that the acceleration of massive objects disrupts the balance of spacetime, generating oscillations known as gravity waves. Researchers will focus more on nanohertz gravitational waves, opening a new scientific direction in nanohertz gravitational wave astronomy. He also noted that China would continue to maintain its leading position in low-frequency radio astronomy worldwide.
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, such as the Indian Pulsar Timing Array and the South African Pulsar Timing Array, have also joined this field.