LIGO的GW150914/GW170817,是引力波信号?还是电网啁啾(Chirps)/涟漪(Ripples)信号?这是一个问题。

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引力波是否存在?温伯格在"解释世界"的这本书中有如下的一段话。

In Newton's theory the gravitational force at a given point and a given time depends on the positions of all masses at the same time, so a sudden change of any of the positions (such as a flare on the surface of the Sun) produces an instantaneous change in gravitational forces everywhere. This is was in conflict with the principles of Einstein's 1905 special theory of relativity that no influence can travel faster than light. This pointed to a clear need to seek modified theory of gravitation. In Einstein's general theory a sudden change in the position of a mass will produce a change in the gravitational field in the immediate neighborhood of the mass which then propagates at the speed of light to greater distances.
解释世界:现代科学的发现 (To Explain the World: The Discovery of Modern Science)

这段话把牛顿力学,狭义相对论,广义相对论串起来讲。为了克服牛顿力学的万有引力全宇宙瞬时传递这个问题点(超距作用),爱因斯坦用狭义相对论和广义相对论逼出了引力波这个概念。我们在这儿不是质疑引力波的存在,而是质疑LIGO真的探测到了引力波吗?

LIGO引力波测量的问题点是没有重整化(renormalization)。

把所有变量放在一个层次上使用傅立叶变换和小波分析进行计算分析，无法排除各种不同层次的变量的相互干扰和影响。

标准理论利用自发对称破缺成功地对强力，弱力和电磁力进行了重整化(renormalization)操作，但是对引力迄今还还没有成功地重整化。弦论宣称成功地重整化了引力，但是无法实验验证。

没有重整化理论武装的LIGO引力波测量，可能是一个笑话，在各种各样噪声信号[比如电网啁啾(Chirp)信号(次同步/超同步振荡信号)]找到了接近光速同步的信号，就惊喜地宣布找到了。

LIGO的信号是时空的涟漪(Ripples)信号,还是电网的涟漪信号,这是一个问题。

LIGO宣称第三次测到了引力波信号(GW170104),LIGO真的测到了引力波信号?

在Frequently Asked Questions[1]中,LIGO宣称考虑了三个环境要素: ground motions, temperature variations and power grid fluctuations。让我们来看看power grid对LIGO的影响。

两个巨型装置使用Servo controls,装备有许多交流马达及相关控制设备,虽然时间上相差10ms,空间上间隔3000km,由于是连接在同一个美国电网上,也就是说两个装置实际上是通过光速电磁波连在一起的。导致GW150914等引力波信号十分可疑[2]。

如上LIGO的论文和FAQ的宣称,电网波动时,有ac-power line monitors[3]监视,可以排除坏数据。问题是美国的监视装置(PMU,Phasor Measurement Unit)只能监视工频(60Hz)相量的偏移,对次同步振荡(比如30Hz)和超同步振荡(比如120Hz)的衰减变化很快信号无法监视和记录。

在论文[3],作者认为电网对装置的影响只有一个工频(60Hz)电压相量。作者根本没有考虑到电网除了稳态的,振幅变化较少的工频电压相量以外,还存在各种各样衰减变化很快的次同步振荡和超同步振荡信号。

论文[17]提到了60Hz and harmonics,电网的基波60Hz,3次(180Hz)/5次(300Hz)谐波等固定存在的频率分量很容易排除,但是不长时存在的电网啁啾(Chirps)信号(次同步振荡信号)呢?

现在新能源(风力发电,太阳能发电)不断增多,电力电子设备不断增多,导致各种次同步振荡(SSO, Sub-synchronous Oscillation)出现的越来越频繁,中国国家电网公司已在新疆电网安装了"次同步振荡检测系统"[4],美国还没有类似的系统。

这儿有两篇论文介绍了作者Policarpo Yoshin Ulianov(巴西人工智能专家)运用信号处理,得出GW150914是美国电网32.5Hz的次同步振荡信号的结论[5,6]。

参照论文"HVDC引起次同步振荡暂态扰动风险的机理分析"[7]:"由图3可以看出，被激发的次同步振荡具有初值高、衰减快的特点。因此，绥中电厂的次同步振荡现象并非由小扰动电气负阻尼造成的，而是由HVDC 造成的大扰动暂态现象"。虽然"转速偏差"是力学系的有功功率变化量,但是如果对电气系瞬时值电压电流进行频谱分析和小波波形拟合处理,是可以取得类似GW150914的初值高、衰减快的信号波形的。

汉明(Richard Wesley Hamming)说[8]:"You Get What You Measure". 他说到: "I repeat the story Eddington told about the fisherman who went fishing with a net. They examined the size of the fish they caught and concluded there was a minimum size to the fish in the sea. The instrument you use clearly affects what you see." 现在LIGO没有汉明这样的一流工程技术人员把关,使人不得不感叹美国工程技术的衰落。

"You Get What You Measure",LIGO测到了引力波了吗?

最近GW170817探测论文见[9],我们看到这些专家还是没有考虑电网其他暂态变化很快并消失的频率分量(次同步和超同步分量)。

LIGO需要证明GW150914/GW12226/GW170104/GW170814/GW170817不是power grid flucations的电网次同步振荡信号(Sub-synchronous Oscillation)。需要马上把美国电网解列运行,彻底断开两个装置之间的电磁联系。如果技术上不能把北美电网解列成两个大网运行,至少需要把LIGO的其中一个装置的电网搞成孤岛运行。并同时需要追加监视电网次同步和超同步分量装置,因为这些暂态分量会相隔最大直线光速时间10ms以内出现在LIGO的两个装置中不断地给出各种伪GW信号。在Virgo装置也需要安装监视电网次同步和超同步分量装置。

  1. LIGO Frequently Asked Questions (LINK)
  2. Observation of Gravitational Waves from a Binary Black Hole Merger(LINK)
  3. Environmental Influences on the LIGO Gravitational Wave Detectors during the 6th Science Run, A. Effler, et. al(LINK)
  4. http://www.weidu8.net/wx/1005147968046913",《新疆电网次同步振荡监控系统的建设与探索》(链接断)
    高比例可再生能源电力系统的协同优化运行技术展望,姚良忠etc.
    ２００９年、２０１１年、２０１５年美国德州、中国河北、中国新疆等地相继发生风电场经串联补偿或直流送出系统的振荡事件,如新疆现场发现振荡中同时存在次同步和超同步分量,且超同步分量幅值更大,引起了国内外学术界的极大关注.[20-22](似乎只有华人学者在研究电网次同步振荡现象,美国学术界已没有人搞电力研究了吗?)
    [20]Huakun Liu,Xiaorong Xie, Chuanyu Zhang,Yu Li,Hui Liu,,Yinghong Hu．Quantitative SSR Analysis of Series-Compensated DFIG-Based Wind Farms Using Aggregated RLC Circuit Model[J]．IEEE Trans on Power Systems,2017,32(1):pp:474-483.
    [21]Meng Wu, Le Xie, Lin Cheng, Rongfu Sun．A Study on The Impact of Wind Farm Spatial Distribution on Power System Sub-Synchronous Oscillations[J]．IEEE Transon Power Systems, 2016,31(3)．pp:2154 - 2162
    [22]袁小明,程时杰,胡家兵．电力电子化电力系统多尺度电压功角动态稳定问题 [J]．中国电机工程学报,2016,36(19):5145G5154．YUAN Xiaoming,CHENG Shijie,HU Jiabing．Multi-time scale voltage and power angle dynamics in power electronics dominated large power systems[J]．Proceedings of the CSEE, 2016,36(19),pp:5145-5154
  5. http://gpcpublishing.com/index.php?journal=gjp&page=article&op=view&path%5B%5D=461, Light fields are also affected by gravitational waves! Presenting strong evidence that LIGO did not detect gravitational waves in the GW150914 event, Policarpo Yoshin Ulianov(LINK),(链接断)
  6. Was LIGO’s Gravitational Wave Detection a False Alarm?(LINK)
  7. HVDC引起次同步振荡暂态扰动风险的机理分析(张鹏,毕天姝)
  8. Hamming, "You Get What You Measure" (June 1, 1995) (You Tube)
  9. GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral(LINK)
    Figure 1 illustrates the data as they were analyzed to determine astrophysical source properties. After data collection, several independently measured terrestrial contributions to the detector noise were subtracted from the LIGO data using Wiener filtering [66], as described in [67–70]. This subtraction removed calibration lines and 60Hz ac power mains harmonics from both LIGO data streams.==>60Hz是电网基波,电网其他暂态变化很快并消失的频率分量(次同步和超同步分量)考虑了吗?
    [66] R. G. Brown and P. Y. C. Hwang, Introduction to Random Signals and Applied Kalman Filtering with Matlab Exercises (Wiley, New York, 2012).
    [67] J. C. Driggers et al., Technical Report No. LIGOP1700260, 2017.
    [68] J. C. Driggers, M. Evans, K. Pepper, and R. Adhikari, Rev. Sci. Instrum. 83, 024501 (2012).
    [69] G. D. Meadors, K. Kawabe, and K. Riles, Classical Quantum Gravity 31, 105014 (2014).
    [70] V. Tiwari et al., Classical Quantum Gravity 32, 165014(2015).
  10. 新能源电力系统次同步振荡问题研究综述(电工技术学报)
  11. 大规模风电场并网系统次同步振荡研究综述
  12. 电力系统次同步和超同步谐波相量的检测方法(谢小荣etc)
  13. LIGO Document P1500238-v24(LINK)
    Characterization of transient noise in Advanced LIGO relevant to gravitational wave signal GW150914(PDF, LINK)
    引用:A network of sensors is employed such that global-scale environmental disturbances that could influence the detectors, such as electromagnetic disturbances in the atmosphere or transient fluctuations in the power grid, are redundantly monitored using PEM sensors that are significantly more sensitive to these disturbances than the detectors themselves.
    请问LIGO的PEM sensors能检测和记录电网(power grid)次同步振荡信号吗?
  14. https://www.gw-openscience.org/, Gravitational Wave Open Science Center
  15. https://www.ligo.caltech.edu/, LIGO, Laser Interferometer Gravitational-Wave Observatory
  16. http://www.nbi.ku.dk/gravitational-waves/, Gravitational Waves and Cosmic Microwave Background
  17. The Sensitivity of the Advanced LIGO Detectors at the Beginning of Gravitational Wave Astronomy(PDF,arxiv.org/pdf/1604.00439.pdf)
    The narrowband features in the sensitivity plots shown in Fig. 5 are caused by power lines (60Hz and harmonics), suspension mechanical resonances, and excitations that are deliberately added to the instrument for calibration and alignment purposes. These very narrow lines are easily excluded from the data analysis, while the broadband noise inevitably limits the instrument sensitivity. The latter is therefore a more important topic of investigation.
    基波60Hz,3次(180Hz)/5次(300Hz)谐波等固定存在的频率分量很容易排除,但是电网啁啾(Chirps)信号(次同步振荡信号)呢?
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