标题： 评论《Shapiro时间延迟的模型依赖性以及“引力速度/光速”争议》 显示英文标题

标题： Comment on 'Model-dependence of Shapiro time delay and the "speed of gravity/speed of light" controversy'

摘要： 在2004年发表于《经典与量子引力》的论文中，第21卷，第3803页，Carlip使用了一种矢量-张量引力理论，计算了移动引力透镜引起的Shapiro时间延迟。他声称，超出Shapiro延迟静态部分的v/c阶相对论修正依赖于光速c，因此Fomalont-Kopeikin实验对引力速度c_g不敏感。在本信中，我们分析了Carlip的计算，并证明它暗示了一个基于引力速度恒定原理的引力动力学（非度规）单位系统，但它与基于光速恒定原理和SI度规（电磁动力学）单位系统的天文学距离测量的实际方法无关。将理论上可接受但实际不可测量的Carlip坐标重新调整到JPL星历中使用的SI度规系统，显示出Shapiro时间延迟静态部分的速度相关修正确实依赖于引力速度c_g，如Kopeikin在《经典与量子引力》2004年第21卷第1页所展示的。这一分析阐明了在引力实验的物理意义解释中采用度规系统单位的重要性。 显示英文摘要

摘要： In a recent paper published in Classical and Quantum Gravity, 2004, vol. 21, p. 3803 Carlip used a vector-tensor theory of gravity to calculate the Shapiro time delay by a moving gravitational lens. He claimed that the relativistic correction of the order of v/c beyond the static part of the Shapiro delay depends on the speed of light c and, hence, the Fomalont-Kopeikin experiment is not sensitive to the speed of gravity c_g. In this letter we analyze Carlip's calculation and demonstrate that it implies a gravitodynamic (non-metric) system of units based on the principle of the constancy of the speed of gravity but it is disconnected from the practical method of measurement of astronomical distances based on the principle of the constancy of the speed of light and the SI metric (electrodynamic) system of units. Re-adjustment of theoretically-admissible but practically unmeasurable Carlip's coordinates to the SI metric system of units used in JPL ephemeris, reveals that the velocity-dependent correction to the static part of the Shapiro time delay does depend on the speed of gravity c_g as shown by Kopeikin in Classical and Quantum Gravity, 2004, vol. 21, p. 1. This analysis elucidates the importance of employing the metric system of units for physically meaningful interpretation of gravitational experiments.