Super amplification of lunar response to gravitational waves driven by thick crust

TL;DR

This study demonstrates that the Moon's thick-crust regions, especially near the South Pole-Aitken basin, can significantly amplify gravitational waves, highlighting their importance for future lunar GW detection efforts.

Contribution

The paper provides the first comprehensive numerical simulation of lunar GW response considering topography and interior heterogeneity, revealing regions with amplification ratios over 2 and reaching tens at certain frequencies.

Findings

Most lunar regions amplify GWs over 2 times.

Amplification reaches tens at ~0.015 Hz near SPA basin.

Thick-crust regions are critical for GW amplification.

Abstract

The Moon has been long regarded as a natural resonator of gravitational waves (GWs) since 1960, showing great potential to fill the frequency gap left behind GW detections by ground- or space-based laser interferometry. However, the spatial variation of this amplification capacity on the Moon remains unclear. Here, we numerically simulate the lunar response to GWs by fully considering the fluctuant topography and laterally heterogeneous interior structures. Our results show that most regions on the Moon can amplify GWs with a ratio over 2, a finding significantly higher than previous estimations. Particularly, the amplification ratio can even reach factors of tens at the resonant frequency of ~0.015 Hz on the highlands surrounding the South Pole-Aitken (SPA) basin, where the regional crust is the thickest. Our findings establish the thick-crust regions as critical zones of GW amplification, which is essential for future landing site selection and instrumental setting for GW detection on the Moon.