Editorial Vol.4(1)

Cornell University - arXiv, 2019

This study illustrates why it is physically impossible that LIGO's interferometers can really detect motions whose order of magnitude should be – as expected-10-19 meters (1/10,000 the size of a proton). And finally it shows why gravity – as linked to the universal inertia according to the Mach's Principle-does not need any wave/energy to instantaneously synchronize.

International Journal of Multidisciplinary Research and Growth Evaluation, 2022

Detection of Gravitational waves opened a new path for cosmological study in a new approach. From the detection of gravitational waves signal by advanced LIGO, its research climbed the peak. After the collaboration of LIGO and Virgo, several observations get collected from different sources of binary systems like black holes, binary neutron stars even both binary black hole and neutron star. The rigorous detection of gravitational signals may provide an additional thrust in the study of complex binary systems, dark matter, dark energy, Hubble constant, etc. In this review paper, we went through multiple research manuscripts to analyze gravitational wave signals. Here we have reviewed the history and current situation of gravitational waves detection, and we explained the concept and process of detection. Also, we go through different parts of a detector and their working. Then multiple gravitational wave signals are focused, originated from various sources and then found correlation...

As a result of technological development of the second half of the twentieth century, Astronomy suffers big change in its methods that it makes its appearance of observation science to become also a new experimental science, where they appear numerous branches. The advancement of knowledge in Astronomy enabled to establish conjectures about the origin of the Universe that would have arisen through the Big Bang, to identify the existence of a massive black hole in the center of the Milky Way, the discovery of water on Mars, Pluto's demotion to dwarf planet, the existence of exoplanets similar to Earth outside the solar system and the discovery of matter and dark energy in the Universe.

2021

The next generation of ground-based gravitational-wave detectors will observe coalescences of black holes and neutron stars throughout the cosmos, thousands of them with exceptional fidelity. The Science Book is the result of a 3-year effort to study the science capabilities of networks of next generation detectors. Such networks would make it possible to address unsolved problems in numerous areas of physics and astronomy, from Cosmology to Beyond the Standard Model of particle physics, and how they could provide insights into workings of strongly gravitating systems, astrophysics of compact objects and the nature of dense matter. It is inevitable that observatories of such depth and finesse will make new discoveries inaccessible to other windows of observation. In addition to laying out the rich science potential of the next generation of detectors, this report provides specific science targets in five different areas in physics and astronomy and the sensitivity requirements to ac...

Study of the Cosmos, at best, is considered a semi-scientific discipline, primarily because the la-boratory for carrying out measurements and tests of theories (the Cosmos) has been largely inac-cessible for centuries. The cosmic vista into the yonder, however, continued to fascinate humankind due to its inherent beauty and sheer curiosity. The invention of the optical telescope more than five centuries back, however, led to the opening of observational cosmology as a scientific discipline with firm experimental basis. However, the investigations based on visible light posed obvious limitations for the range of such observational cosmology. The advent of the radio telescope in the first half of the 20th century marked a fundamental new step in the progress of this branch of science. There has been no looking back in the march of knowledge in the discipline since then. A whole new vista was laid bare as a result of this development, leading to the discovery of altogether new celestial objects, such as quasars and pulsars and still newer galaxies. The parallel progress of the physics of fundamental constituents of the material world and their interactions led to an interesting merger of these two branches of physical sciences, yielding absolutely astounding knowledge of the nature and evolution of the Universe. New concepts of dark energy and dark matter thought to constitute the dominant share of the Universe were brought to light as a result of these new observations and theoretical ideas. This brief article aims to provide an overview of these exciting developments in the field of cosmology and the associated physics.

In 1933, not long after Pauli postulated the existence of the neutrino in order to preserve conservation of energy in beta decay processes, Niels Bohr raised the following question: " What is the difference between [neutrinos] and the quanta of gravitational waves? " At that time the neutrino was thought to have no mass or charge, and travel at the speed of light with almost no interaction with matter. These unusual properties were also theoretically predicted for gravitational waves. Subsequently, physicists have concluded that neutrinos have spin = 1/2, and that they can " flavor-shift " between different types of neutrinos. The latter phenomenon suggests that neutrinos have tiny masses and therefore cannot have v = c. So it would look like Bohr's question has been answered. While both gravitational waves and neutrinos should be ubiquitous in the cosmos, and can travel through gas, dust, stars, planets and whole galaxies largely unimpeded, they are thought to differ in spin (1/2 versus 2), mass, and speed. On the other hand, nature has a history of serving up results that were previously considered " impossible ". So maybe it is not unreasonable to take another look at Bohr's question. My interest in this question stems from a theory I have worked on for 40 years or so, called Discrete Scale Relativity [ http://www3.amherst.edu/~rloldershaw ]. For our present concern with gravitational waves and neutrinos, we need to mention DSR's main principle of discrete cosmological self-similarity. Roughly speaking this principle proposes that the cosmos is organized into discrete hierarchy of cosmological Scales, like the Atomic Scale, the Stellar Scale, and the Galactic Scale, which are all highly self-similar to one another. DSR also predicted in 1987 (Astrophys. J. 322, 34-36, 1987) that the dark matter was composed of stellar mass black holes. This prediction was largely ignored in favor of WIMP candidates, but the positive MACHO and LIGO results, combined with 30 years of negative results for WIMPs, has given increasing credibility to the idea that stellar-mass primordial black holes will solve the dark matter enigma. In 2015 the LIGO collaboration observed gravitational waves for the first time, and now in conjunction with the VIRGO collaboration, several more gravitational wave events have been detected and characterized. So far the results have vindicated Einstein's General Relativity in all respects. It is now virtually certain that the cosmos is pervaded by astronomical numbers of these ghostly oscillations of space-time that are generated whenever stellar-mass ultracompact objects (black holes and neutron stars) interact strongly. The GWs travel at light speed, they have no

arXiv preprint astro-ph/ …, 2001

Gravitational-wave detectors with sensitivities sufficient to measure the radiation from astrophysical sources are rapidly coming into existence. By the end of this decade, there will exist several ground-based instruments in North America, Europe, and Japan, and the joint American-European space-based antenna LISA should be either approaching orbit or in final commissioning in preparation for launch. The goal of these instruments will be to open the field of gravitational-wave astronomy: using gravitational radiation as an observational window on astrophysics and the universe. In this article, we summarize the current status of the various detectors currently being developed, as well as future plans. We also discuss the scientific reach of these instruments, outlining what gravitational-wave astronomy is likely to teach us about the universe.