Lecture

Gravitational Waves: Detection and Quadrupole Formula

Graph Chat

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

In course

PHYS-427: Relativity and cosmology I

Introduce the students to general relativity and its classical tests. ...

Description

This lecture covers the production of gravitational waves, linearized Einstein equations, the first detection of gravitational waves, and the quadrupole formula. It explains the characteristics of gravitational waves, the Lorenz gauge, and the concept of the quadrupole moment tensor. The lecture also delves into the observation of gravitational waves on 14/09/2015, detailing the strain, frequency, and detection at the Hanford and Livingston LIGO detectors.

Official source

Ontological neighbourhood

Physics

Relativity: General relativity

Related concepts (32)

Gravitational wave

Gravitational waves are waves of the intensity of gravity that are generated by the accelerated masses of an orbital binary system, and propagate as waves outward from their source at the speed of light. They were first proposed by Oliver Heaviside in 1893 and then later by Henri Poincaré in 1905 as waves similar to electromagnetic waves but the gravitational equivalent. Gravitational waves were later predicted in 1916 by Albert Einstein on the basis of his general theory of relativity as ripples in spacetime.

Gravitational-wave astronomy

Gravitational-wave astronomy is an emerging field of science, concerning the observations of gravitational waves (minute distortions of spacetime predicted by Albert Einstein's theory of general relativity) to collect relatively unique data and make inferences about objects such as neutron stars and black holes, events such as supernovae, and processes including those of the early universe shortly after the Big Bang.

First observation of gravitational waves

The first direct observation of gravitational waves was made on 14 September 2015 and was announced by the LIGO and Virgo collaborations on 11 February 2016. Previously, gravitational waves had been inferred only indirectly, via their effect on the timing of pulsars in binary star systems. The waveform, detected by both LIGO observatories, matched the predictions of general relativity for a gravitational wave emanating from the inward spiral and merger of a pair of black holes of around 36 and 29 solar masses and the subsequent "ringdown" of the single resulting black hole.

Gravitational wave background

The gravitational wave background (also GWB and stochastic background) is a random background of gravitational waves permeating the Universe, which is detectable by gravitational-wave experiments, like pulsar timing arrays. The signal may be intrinsically random, like from stochastic processes in the early Universe, or may be produced by an incoherent superposition of a large number of weak independent unresolved gravitational-wave sources, like supermassive black-hole binaries.

Gravitational redshift

In physics and general relativity, gravitational redshift (known as Einstein shift in older literature) is the phenomenon that electromagnetic waves or photons travelling out of a gravitational well (seem to) lose energy. This loss of energy corresponds to a decrease in the wave frequency and increase in the wavelength, known more generally as a redshift. The opposite effect, in which photons (seem to) gain energy when travelling into a gravitational well, is known as a gravitational blueshift (a type of blueshift).

Related lectures (64)

Gravitational Waves: Observations and Implications

Explores the detection of gravitational waves, focusing on the first observation of a binary black hole merger and its implications for astrophysics.

Gravitational-Wave Transient Catalog: Insights and Challenges

Explores the Gravitational-Wave Transient Catalog 2 and the challenges in distinguishing compact bodies, emphasizing the need for accurate waveform models and the discovery potential in gravitational physics.

Special and General Relativity

Introduces special and general relativity, Einstein equations, and gravitational dynamics.

Solar Radiation Spectrum: Understanding Earth's Energy Balance

Explores the solar radiation spectrum, Earth's energy balance, gravitational wells, and space debris challenges.

Gravitational Waves: Energy and Flux