GPT-4: Scientists worldwide have discovered a signal in the timing of pulsars that suggests the presence of giant, long-wavelength gravitational waves. This discovery, while not yet a confirmed detection of these waves, is a significant step forward in gravitational wave astronomy. The signal is believed to be caused by supermassive black hole mergers, but further research is needed to confirm this. The findings could open a new era of nanohertz gravitational wave astronomy, allowing scientists to study the properties of supermassive black holes in greater detail.