SO(10) grand unified symmetry breaks through flipped SU(5), and the breaking leaves behind superheavy magnetic monopoles. Confinement connects monopole-antimonopole pairs with strings, creating a network of quasi-stable bound states. Partial inflation dilutes the network without destroying it.
When the string segments eventually collapse, the monopoles at their endpoints are released. If the parameters are right, the released monopole density is observable.
Simultaneously, the quasi-stable string network itself emits gravitational waves. The frequencies fall in the Hz-to-kHz range — exactly where LIGO, LISA, and proposed detectors operate.
The chain: symmetry breaking produces monopoles → confinement creates strings between them → inflation leaves the network quasi-stable → decay releases monopoles and gravitational waves at human-accessible frequencies. Each step is necessary. Remove any link and the observable signal vanishes.
What makes this compelling is not any single step but the fact that the entire chain is internally consistent. The same symmetry breaking pattern that produces the monopoles also produces the strings. The same cosmological evolution that dilutes the network also stabilizes it at the right density. The observable signals — monopole flux and gravitational wave spectrum — are correlated because they share a common origin.
A single mechanism, observed through two different instruments. The chain is the prediction.