Exactly how space gets curved is still an open question. One possibility is that the force of gravity is carried by a particle, like how electricity is carried by the electron or how light is carried by the photon. This hypothetical particle has been dubbed the graviton, but there’s no guarantee that the graviton exists at all.
Two groups of scientists may have finally solved that problem, by proposing an experiment to determine if the graviton exists without ever observing it directly. The experiment involves trying to get two particles to quantum entangle using their gravitational interactions, and if they’re successful it could confirm that quantum gravity exists after all.