All stars already sang to themselves. The outer layers of every star rang constantly at a multitude of frequencies, like an eternally chiming bell. The great seismic modes tracked oscillations that plunged deep into the star, down to the caustic surface just above its fusing core. Those oscillations were modest in a star of dwarf type, like Delta Pavonis. But the singer tuned itself to them, swinging around the star in its equatorial rotation frame, pumping gravitational energy into the star at precisely the right resonant frequencies to enhance the oscillations. The singer was what the mammals would have called a graver, a gravitational laser.
In the heart of the singer a microscopic closed cosmic string, a tiny relic of the rapidly cooling early universe, had been tugged out of the seething foam of the quantum vacuum. The string was barely a scratch compared with the largest cosmic flaws, but it would suffice for the singer’s purposes. It was tugged and elongated like a loop of toffee, inflated with the same vacuum phase energy that the singer tapped for all its needs, until it had macroscopic size and macroscopic mass-energy density. Then the string was deftly knotted into a figure-of-eight configuration and plucked, generating a narrow cone of throbbing gravitational waves.