Gravity

2021 ◽  
Author(s):  
James B. Hartle
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Gravitational Waves ◽  
Undergraduate Curriculum ◽  
Physics First ◽  
Cambridge University ◽  
Introductory Course ◽  
Modern Physics ◽  
The Subject ◽  
Curriculum Making

Einstein's theory of general relativity is a cornerstone of modern physics. It also touches upon a wealth of topics that students find fascinating – black holes, warped spacetime, gravitational waves, and cosmology. Now reissued by Cambridge University Press, this ground-breaking text helped to bring general relativity into the undergraduate curriculum, making it accessible to virtually all physics majors. One of the pioneers of the 'physics-first' approach to the subject, renowned relativist James B. Hartle, recognized that there is typically not enough time in a short introductory course for the traditional, mathematics-first, approach. In this text, he provides a fluent and accessible physics-first introduction to general relativity that begins with the essential physical applications and uses a minimum of new mathematics. This market-leading text is ideal for a one-semester course for undergraduates, with only introductory mechanics as a prerequisite.

Beyond the Schwarzschild Metric

2018 ◽  
Author(s):  
David M. Wittman
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Gravitational Waves ◽  
Test Particle ◽  
Direct Detection ◽  
Relativistic Effects ◽  
Big Bang ◽  
Clusters Of Galaxies ◽  
General Relativistic ◽  
The Universe

General relativity explains much more than the spacetime around static spherical masses.We briefly assess general relativity in the larger context of physical theories, then explore various general relativistic effects that have no Newtonian analog. First, source massmotion gives rise to gravitomagnetic effects on test particles.These effects also depend on the velocity of the test particle, which has substantial implications for orbits around black holes to be further explored in Chapter 20. Second, any changes in the sourcemass ripple outward as gravitational waves, and we tell the century‐long story from the prediction of gravitational waves to their first direct detection in 2015. Third, the deflection of light by galaxies and clusters of galaxies allows us to map the amount and distribution of mass in the universe in astonishing detail. Finally, general relativity enables modeling the universe as a whole, and we explore the resulting Big Bang cosmology.

An introduction to general relativity, black holes and gravitational waves

2011 ◽  
Author(s):  
Nora Bretón ◽  
Luis Arturo Ureña-López ◽  
Hugo Aurelio Morales-Técotl ◽  
Román Linares-Romero ◽  
Elí Santos-Rodríguez ◽  
...  
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Gravitational Waves

scholarly journals Black Holes, Gravitational Waves and Quantum Gravity

2021 ◽  
pp. 1-11
Author(s):  
W. F. Chagas-Filho
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Gravitational Field ◽  
Quantum Gravity ◽  
Gravitational Waves ◽  
Loop Quantum Gravity ◽  
Canonical Quantization ◽  
Planck Length ◽  
Basic Ideas ◽  
Area And Volume

Loop Quantum Gravity is a theory that attempts to describe the quantum mechanics of the gravitational field based on the canonical quantization of General Relativity. According to Loop Quantum Gravity, in a gravitational field, geometric quantities such as area and volume are quantized in terms of the Planck length. In this paper we present the basic ideas for a future, mathematically more rigorous, attempt to combine black holes and gravitational waves using the quantization of geometric quantities introduced by Loop Quantum Gravity.

Detecting Blackholes through Gravitational Waves

2014 ◽  
Author(s):  
Charles D. Bailyn
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Electromagnetic Radiation ◽  
Gravitational Waves ◽  
Gravitational Radiation ◽  
Stellar Mass ◽  
Supermassive Black Holes ◽  
Current Technology

This chapter looks at the detection of black holes through gravitational waves. While further improvements can be expected in the ability to detect and measure electromagnetic radiation, it is possible that the next great advances in observational astrophysics will come from the detection of other kinds of information altogether. Currently, there is a great excitement about the possibility of directly detecting an entirely new “celestial messenger,” namely, gravitational radiation. The existence of gravitational waves is a prediction of general relativity, and current technology is very close to being able to detect them directly. The strongest sources of gravitational radiation are expected to be merging black holes. Since such mergers are expected to occur, both between stellar-mass and supermassive black holes, the detection of gravitational radiation would provide a new way not only to explore gravitational physics but also to look for and to study celestial black holes.

The Direct Detection of Gravitational Waves

2018 ◽  
pp. 106-109
Author(s):  
Alvaro De Rújula
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Gravitational Waves ◽  
Direct Detection ◽  
Space Time ◽  
New Era ◽  
The Third ◽  
Perfect Storm

Gravitational waves emitted by black hole mergers. The first LIGO event: GW150917, the coalescence of two black holes of twenty nine and thirty six solar masses into one of “only” sixty two. The remaining three solar masses were emitted as energy in gravitational waves, a gigantic and perfect storm in the fabric of space-time. This is the dawn of a new era: The opening of the third “window” through which to look at the sky. Yet another triumph of general relativity. How much progress astrophysics has made since my time as a student.

scholarly journals Gravitational waves from disks around spinning black holes: Simulations in full general relativity

2021 ◽  
Vol 103 (4) ◽  
Author(s):  
Erik Wessel ◽  
Vasileios Paschalidis ◽  
Antonios Tsokaros ◽  
Milton Ruiz ◽  
Stuart L. Shapiro
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Gravitational Waves

scholarly journals Recent Observations of Gravitational Waves by LIGO and Virgo Detectors

Universe ◽  
2021 ◽  
Vol 7 (5) ◽  
pp. 137
Author(s):  
Andrzej Królak ◽  
Paritosh Verma
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Neutron Stars ◽  
Gravitational Waves ◽  
Gravitational Radiation ◽  
Direct Detection ◽  
Nobel Prize Winner ◽  
Short Introduction ◽  
Interferometric Detectors ◽  
Laser Interferometric

In this paper we present the most recent observations of gravitational waves (GWs) by LIGO and Virgo detectors. We also discuss contributions of the recent Nobel prize winner, Sir Roger Penrose to understanding gravitational radiation and black holes (BHs). We make a short introduction to GW phenomenon in general relativity (GR) and we present main sources of detectable GW signals. We describe the laser interferometric detectors that made the first observations of GWs. We briefly discuss the first direct detection of GW signal that originated from a merger of two BHs and the first detection of GW signal form merger of two neutron stars (NSs). Finally we present in more detail the observations of GW signals made during the first half of the most recent observing run of the LIGO and Virgo projects. Finally we present prospects for future GW observations.

Elements of causality

2020 ◽  
pp. 21-84
Author(s):  
Piotr T. Chruściel
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Energy Conditions ◽  
Lorentzian Manifolds ◽  
Area Theorem ◽  
Causal Relations ◽  
Singularity Theorems ◽  
The Subject ◽  
Incompleteness Theorems ◽  
Uniqueness Theory

A standard part of studies of black holes, and in fact of mathematical general relativity, is causality theory, which is the study of causal relations on Lorentzian manifolds. An essential issue here is understanding the influence of energy conditions on the causality relations. The highlights of such studies include the incompleteness theorems, known also as singularity theorems, of Penrose, Hawking and Geroch, the area theorem of Hawking, and the topology theorems of Hawking and others. The aim of this chapter is to provide an introduction to the subject, with a complete exposition of those topics which are needed for the global treatment of the uniqueness theory of black holes. In particular we provide a coherent introduction to causality theory for metrics which are twice differentiable.

scholarly journals Quantum Black Holes in the Sky

Universe ◽  
2020 ◽  
Vol 6 (3) ◽  
pp. 43 ◽  
Author(s):  
Jahed Abedi ◽  
Niayesh Afshordi ◽  
Naritaka Oshita ◽  
Qingwen Wang
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Review Article ◽  
Compact Objects ◽  
Theoretical Underpinning ◽  
The Past ◽  
Einstein’S General Relativity

Black Holes are possibly the most enigmatic objects in our universe. From their detection in gravitational waves upon their mergers, to their snapshot eating at the centres of galaxies, black hole astrophysics has undergone an observational renaissance in the past four years. Nevertheless, they remain active playgrounds for strong gravity and quantum effects, where novel aspects of the elusive theory of quantum gravity may be hard at work. In this review article, we provide an overview of the strong motivations for why “Quantum Black Holes” may be radically different from their classical counterparts in Einstein’s General Relativity. We then discuss the observational signatures of quantum black holes, focusing on gravitational wave echoes as smoking guns for quantum horizons (or exotic compact objects), which have led to significant recent excitement and activity. We review the theoretical underpinning of gravitational wave echoes and critically examine the seemingly contradictory observational claims regarding their (non-)existence. Finally, we discuss the future theoretical and observational landscape for unraveling the “Quantum Black Holes in the Sky”.

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