Tootfinder

Frequency Differences between Clocks on the Earth and the Moon
Mingyue Zhang, J\"urgen M\"uller, Sergei M. Kopeikin
https://arxiv.org/abs/2506.16377

Frequency Differences between Clocks on the Earth and the Moon
Based on general relativity, clock comparisons enable the determination of the gravity potential relative to a stable reference. Lunar surface clocks, owing to the Moon's low-noise conditions, high orbital stability, and broad Earth visibility, are promising reference clocks for global-scale comparisons between terrestrial clocks. Meanwhile, the need for an independent lunar time system-driven by future lunar navigation-requires maintaining links to terrestrial standards. This Letter simulates …

Lie Group Theory of Multipole Moments and Shape of Stationary Rotating Fluid Bodies
Sergei M. Kopeikin (University of Missouri-Columbia, USA)
https://arxiv.org/abs/2505.14712

Lie Group Theory of Multipole Moments and Shape of Stationary Rotating Fluid Bodies
We present a rigorous framework for determining the equilibrium configurations of uniformly rotating, self-gravitating fluid bodies. This work addresses the classical challenge of modeling rotational deformation in celestial objects such as stars and planets. By integrating foundational theory with modern mathematical tools, we develop a unified formalism that enhances the precision and generality of shape modeling in astrophysical contexts. Our method applies Lie group theory to vector flows a…