Mass-Centered Temporal Persistence Around Spherical Objects

Previous studies demonstrated that weak optical fluctuations surrounding suspended metallic spheres exhibit mass-dependent temporal persistence, spatially extended statistical correlations, and source-centered spatiotemporal organization under broadband incoherent illumination. The present study examines this established statistical behavior from a complementary perspective by comparing two spherical objects having approximately equal total mass but substantially different physical size and spatial mass distribution. A high-density tungsten sphere and a larger stainless-steel sphere were measured under the same cylindrical paper-shielding configuration and comparable illumination and imaging conditions. Temporal persistence was evaluated at common image-centered locations using a fixed $3\times3$ patch arrangement. The ensemble-averaged peak-persistence levels were closely comparable despite the substantial difference in sphere size. In contrast, the later-time autocorrelation structure differed more clearly: positive long-lag persistence was present in both conditions, but the tungsten measurements exhibited a larger ensemble-averaged positive long-lag contribution and a more persistent positive autocorrelation component over much of the 0.5--2.0~s lag interval. These results show that similar peak-persistence levels can coexist with different long-lag temporal organization. The close agreement in ensemble peak persistence despite substantially different surface-boundary locations is consistent with an object-centered or mass-associated component, whereas the stronger long-lag contribution in the denser tungsten condition suggests an additional sensitivity to spatial mass concentration. Together with earlier same-size, different-mass measurements, the results support a phenomenological picture in which total mass is associated primarily with the overall persistence level, while spatial mass concentration may additionally modulate the long-lag component. Material-specific effects remain a possible contribution and cannot yet be fully separated. Phenomenologically, this distinction is reminiscent of gravitational systems in which the total mass sets the leading global scale, while structural properties can influence additional dynamical behavior. In gravitational-wave tail theory, the leading hereditary tail depends on the total mass of the source rather than on its material surface, providing a physical motivation for testing whether the observed temporal persistence is organized primarily with respect to the object as a whole.