论文标题
重力难题：从英格兰到澳大利亚的“第一舰队”上令人困惑的时钟速率测量值
Gravitational Conundrum: Confusing Clock-Rate Measurements on the "First Fleet" from England to Australia
论文作者
论文摘要
探索的航行通常包括船员中的天文学家，以帮助海上航行。威廉·道斯（William Dawes）是一名英国海军陆战队员，接受过实用天文学训练，被分配到“第一舰队”，这是一支十一艘船舶的车队，于1787年5月前往英格兰，前往植物学湾（澳大利亚悉尼）。预计DAWES还可以通过测量其Shelton Pendulum Clock与Greenwich的校准位置的每日速率来测量局部的任何港口，以测量当地重力加速度，即$ G $。尽管英国的第五名天文学家皇家（Royal）计划在加那利群岛，圣塞巴斯蒂安（Rio de Janeiro）（里奥德·德·贾尼罗（Rio de Janeiro））和桌上湾（Table Bay），第一位车队的指挥官阿瑟·菲利普（Arthur Phillip）的指挥官Arthur Phillip，仅允许Dawes在Rio De Janeaniro的Rio Plock上划分，但Dawes和Nevil Maskelyne计划在加那利群岛，圣塞巴斯蒂安（Rio de Janeiro）和Table Bay获得时钟率测量。因此，除了在新南威尔士州获得的陆基测量值外，我们还只有一组时钟速率测量值。如果重力是影响时钟变化速率的主要因素，则DAWES的测量值为$ -48.067 $ sec，每日（恒星）在里约热内卢（Rio de Janeiro）获得的日期表示局部重力加速，$ G = 9.7946 $ M SEC $^{ - 2} $。另一方面，如果我们采用现代价值，$ g = 9.7878 $ m s $^{ - 2} $，暗示的每日衰减率几乎比Dawes的时钟率确定大30秒，那么差异就超过了普遍的不确定性。这表明摆锤的调节螺母可能被完全转弯所抵消，因此这意味着我们对摆长度长度的假设可能必须重新审视。
Voyages of exploration often included astronomers among their crew to aid with maritime navigation. William Dawes, a British Marine who had been trained in practical astronomy, was assigned to the "First Fleet", a convoy of eleven ships that left England in May 1787 bound for Botany Bay (Sydney, Australia). Dawes was also expected to take measurements of the local gravitational acceleration, $g$, at any port of call by measuring the daily rate by which his Shelton pendulum clock differed from that at Greenwich, its calibration location. Although Dawes and Nevil Maskelyne, Britain's fifth Astronomer Royal, had planned to obtain clock-rate measurements in the Canary Islands, San Sebastian (Rio de Janeiro) and Table Bay, Captain Arthur Phillip, Commander of the First Fleet, only allowed Dawes to disembark the clock in Rio de Janeiro. Therefore, we have just one set of clock-rate measurements from the voyage, in addition to land-based measurements obtained in New South Wales. If gravity was the dominant factor affecting the clock's changing rate, Dawes' measurement of $-48.067$ sec per (sidereal) day obtained in Rio de Janeiro implies a local gravitational acceleration, $g = 9.7946$ m sec$^{-2}$. On the other hand, if we adopt the modern value, $g = 9.7878$ m s$^{-2}$, the implied daily decay rate is almost exactly 30 sec greater than Dawes' clock-rate determination, a difference that is well in excess of the prevailing uncertainties. This suggests that the pendulum's regulator nut may have been offset by a full turn, thus implying that our assumptions regarding the pendulum length may have to be revisited.
