Based on the core premise that uneven matter distribution is a fundamental cosmic characteristic and grounded in the mass field momentum coupling theory, this paper rigorously derives gravitational waves as momentum field fluctuations excited by accelerated motion of objects with uneven matter distribution through classical field theory, vector analysis, and wave equations. The entire derivation adheres to the core conditions of uneven matter distribution () + accelerated motion (). It clarifies that the essential nature of gravitational waves is spacetime fluctuations of the momentum field, propagating at the speed of light as transverse waves. The derivation agrees with the predictions of general relativity in observational characteristics; the two are distinct descriptions of the same physical phenomenon from different theoretical starting points, complementary rather than contradictory. The derivation closes the logical loop between momentum coupling force and gravitational waves: accelerated motion of unevenly distributed matter generates momentum coupling force; periodic evolution of the force excites momentum field fluctuations; the fluctuations propagate at light speed, constituting gravitational waves.
Xiaobin CHEN (Mon,) studied this question.