林金是中国运载火箭技术研究院的杰出科学家;他于1935年4月出生,2016年2月不幸因病逝世.林金教授是卫星导航技术的著名专家,他那独创和新颖的基于火箭测量的重新定义空间、时间的见解和方法,在科学界受到关注并得到高度赞扬.林金教授还是国际宇航研究院院士.“利用光的往返定义时间”,1905年Einstein以此为基础构建了狭义相对论(SR);林金洞察于此,对之作深入的思考.2004年林金在论文中说,Lorentz解释他自己的变换式(LT)时仍用绝对空间、时间,但Einstein却用同时的相对性解释LT.现在我们应重新审视1905年Einstein以光速不变假设为基础的关于同时性的定义——当光信号由位置A传到位置B,并立即返回到A,则有时间关系式tB-tA=tA-tB.……但在2009年林金团队发表一篇论文,报道他们对Einstein光速不变假设的判决性实验检验,它是在中国科学院国家授时中心的高精度TWSTT(双向卫星时间传递)设施上完成的.通过对比单程光信号同时性定义和双程光信号同时性定义的测量机制证明:在有相对运动的情况下双程光信号中的“往”和“返”两个单程信号通过的时间必然是不相等的.在所报告的实验检验中西安临潼地面观测站和乌鲁木齐地面观测站的铯原子钟分别通过鑫诺卫星和中卫一号卫星进行双向时间传递.因此林金教授证明可以用航天技术手段来作“时间tA”和“时间妇”的实际的直接比较.林金还指出,“超过光的速度不可能存在”是从SR的Lorentz因子提出的,太阳系外载人深空宇宙航行的发展要求对这个问题作出回答.他就自主惯性导航提供的一个新理论来分析惯性导航的时间定义和测量机制以及超光速运动.火箭自主惯性导航理论的启发性在于,一个动体可以自己测量自己相对一个惯性系的加速度、速度和位置,作为动体上自带钟固有时间的函数.自主纯惯性导航系统是基于引力场的一个基本性质;即使这个世界上没有光、没有电磁场,纯惯性系统照样工作,照常自主定位、自主测速.在一个假想只有引力场、没有电磁场的世界中,为何3×108m/s会成为动体速度的极限？!宇航员建立了自主精确描述火箭和宇宙飞船在给定惯性系中作任意加速和减速运动的动力学过程.只要开发出新的动力源,宇宙飞船的航行速度不存在上限.林金教授关于光速问题的有关理论和实验工作,不仅是出色的,甚至可能是绝无仅有的.我们仅以此文向他致敬和怀念.%LIN Jin is a top scientist of Chinese Academy of Launch Vehicle Technology.He was born in April 1935,die in February 2016.Prof.LIN was one of the leading experts in satellite space navigation technology and experiments,his highly original and novel approach to the redefinition of space and time based on rocket measurements caused somewhat of a stir among the scientists and won acclaim.Prof.LIN was an academician of International Astronautics Sciences Academy."The definition of time is make full use of the light to and fro between two positions",Einstein constructed the Special Relativity(SR) based upon this idea in 1905.Prof.LIN see clearly on this subject and think deeply.In the year 2004,LIN Jin says in the article:Lorentz himself interpreted Lorentz Transformation(LT)as absolute space and absolute time,but Einstein's interpretation of LT is relative of simultancity.Now,we must re-examine the definition of simultancity proposed by Einstein in 1905,it based upon the postulate of the light speed constancy——when to light signal from position A propagate to position B,and soon back to A,the relation of time is tB-tA =t'A tB.… But in the year 2009,LIN Jin et.al.published an article for the crucial experiment in order to checking Einstein's postulate of the light speed constancy.It was performed at the high precision TWSTT (Two Way Satellite Time Transfer) facility of the National Time Service Center,Chinese Academy of Sciences.By comparison the measurement mechanisms of one way light signal simultaneity and "to-and-fro" two way light signal simultancity,the principle of the crucial experiment has proved:if there exists relative motion,the"uplink" and "downlink" light signal passage times of the"to-and-fro"two way light signal are not equal,so that tB--tA ≠ t'A--tB.The cesium atomic clocks at Xian station and Urumuqi station transferred and exchanged pps time signals via Sino satellite and China Sat-1 satellite.Then,Prof.LIN was proved that the comparison of "time tA " and "time tB " is subject to direct experimental verification by means of space technology.In the opinion of Prof.LIN,"velocities greater than that of light have no possibility of existence" arose from the Lorentz factor of Special Relativity(SR).The development of manned deep space travel out of the solar system demands and answer to this issue.He analyse the definition of time and measurement mechanism of inertial navigation and faster than light issue on the basis of a new theoretical model provided by the autonomous inertial navigation.The unique point worthy of conscious brooding of the theoretical model of rocket autonomous inertial navigation is that a moving body is able to measure its own acceleration、velocity and position in a given inertial system as functions of proper time of the on-board clock in the moving body.In principle,autonomous pure inertial navigation is based on a fundamental feature of gravitational field;even if there were no light,no electromagnetic fields in the world,a pure inertial navigation system works as well,autonomously measuring velocity and position.In a world with only gravitational field,and without electromagnetic fields at all,why should 3×108m/s be the limit of velocity?! The astronaut has established an accurate equation which autonomously and precisely describes arbitrary acceleration and deceleration motion of rockets and spacecraft in a given inertial system.As long as new types of power sources are to be developed,there exist no limit of velocities of spacecraft.The research works on light speed problems of Prof.LIN are brilliant contributions,and perhaps it is never to be seen again.We salute to Prof.LIN,and cherish the memory of this scientist.
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