Ligo
LIGO (Laser Interferometer Gravitational-Wave Observatory) is a large-scale physics experiment designed to detect gravitational waves—ripples in spacetime caused by accelerating massive objects. The observatory consists of two facilities located in the United States, in Livingston, Louisiana and Hanford, Washington, which operate in tandem to identify and characterize gravitational wave signals through laser interferometry. By comparing measurements from both sites, LIGO distinguishes genuine astrophysical signals from local noise, enabling the observation of cataclysmic events such as black hole mergers and neutron star collisions.
In the context of cosmology, LIGO’s data has provided critical evidence for the existence of sub-solar mass objects, which challenges standard stellar evolution models. Recent analyses have identified signals consistent with the merger of primordial black holes, suggesting these compact objects may have formed in the early universe rather than from the collapse of stars. This detection supports theories regarding dark matter candidates and the distribution of mass in the cosmos during its infancy.
The confirmation of sub-solar mass gravitational wave events expands the known population of black holes beyond the typical stellar-mass range. These findings allow astrophysicists to constrain the abundance of primordial black holes and refine models of the early universe’s density fluctuations. Consequently, LIGO serves not only as a tool for observing high-energy astrophysical phenomena but also as a probe for fundamental cosmological questions regarding the origin and composition of the universe.