Original sentence: Geometrodynamics, gravity and inertia are not separate phenomena, they are seen as aspects of interaction with a single field: space-time geometry.In quantumphysics it is hypothesized that inertia is mediated by interaction of matter with a field that has been called a the Higgs field.It is extremely rare for space-time geometry to rotate significantly with respect to the universe as a whole, therefore 'non-rotating frame of reference' is often defined as a frame of reference that doesn't rotate with respect to the universe as a whole.You can do a local measurement with a mechanical instrument like a gyroscope, or you can measure with an interferometric instrument, the instruments will agree on how much (or how little) the local inertial frame of reference rotates with respect to the universe as a whole
Edited sentence: Anyway, in general relativity, gravity and inertia are not separate phenomena, they are seen as aspects of interaction with a single field: space-time geometry.Four interactions are commonly listed as 'The four fundamental forces of nature'.Indeed, in quantumphysics it is hypothesized that inertia is mediated by interaction of matter with a field that has been called a the Higgs field.Inertia deserves to be among that group.Inertia is very much an underappreciated physical phenomenon.It is extremely rare for space-time geometry to rotate significantly with respect to the universe as a whole, therefore 'non-rotating frame of reference' is often defined as a frame of reference that doesn't rotate with respect to the univers as a whole.The preferred frame to understand physics phenomena is the local inertial frame of reference.These are: strong nuclear interaction, weak nuclear interaction, electromagnetic interaction, and gravitation.You can do a local measurement with a mechanical instrument like a gyroscope, or you can measure with an interferometric instrument, the instruments will agree on how much (or how little) the local inertial frame of reference rotates with respect to the distant stars