The concept of gravity as an energy wave without mass is not supported by current scientific understanding. In the framework of general relativity, gravity is described as the curvature of spacetime caused by mass and energy. It is not considered as a wave that degrades as it travels.
In general relativity, the force of gravity is mediated by the exchange of particles called gravitons. However, the hypothetical particle associated with gravity, the graviton, has not yet been directly observed or confirmed by experimental evidence. Theoretical models suggest that if gravitons exist, they would be massless, similar to photons (particles of light).
When it comes to waves, such as electromagnetic waves (including light), they can indeed experience a phenomenon called attenuation or degradation as they propagate through a medium. Attenuation occurs due to interactions with the medium's particles, which can cause absorption or scattering of the energy carried by the wave. However, this concept is not applicable to gravity as described by general relativity.
It's worth noting that our understanding of gravity and the nature of the graviton is an active area of research, and scientists continue to explore and investigate various aspects of gravity to gain a more comprehensive understanding of this fundamental force in the universe.