Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Lecture

Black Holes: Redshift and Gravitational Waves

In courses (2)

PHYS-427: Relativity and cosmology I

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

PHYS-428: Relativity and cosmology II

This course is the basic introduction to modern cosmology. It introduces students to the main concepts and formalism of cosmology, the observational status of Hot Big Bang theory and discusses major physical processes in the early Universe. ...

Description

This lecture covers three problems related to black holes and gravitational waves. The first problem involves understanding the redshift of a photon emitted near a black hole. The second problem explores the degrees of freedom and gauge symmetry of electromagnetic and gravitational waves in different spacetime dimensions. The final problem delves into computing the energy-momentum tensor for gravitational waves, determining if they carry energy and momentum.

Instructor

Victor Gorbenko

Official source

Ontological neighbourhood

Physics

Relativity: General relativity

Related concepts (30)

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 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).

Gravitational-wave observatory

A gravitational-wave detector (used in a gravitational-wave observatory) is any device designed to measure tiny distortions of spacetime called gravitational waves. Since the 1960s, various kinds of gravitational-wave detectors have been built and constantly improved. The present-day generation of laser interferometers has reached the necessary sensitivity to detect gravitational waves from astronomical sources, thus forming the primary tool of gravitational-wave astronomy.

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.

Related lectures (32)

Scattering Structures: From Amplitudes to Black Holes

Explores gauge symmetry, amplitudes, black holes, and fluids, highlighting the interplay between redundancy, diffeomorphisms, and the double copy phenomenon.

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.

Linearized Gravity: Perturbation Theory

Covers linearized gravity, perturbation theory, Einstein equations, and gravitational waves.

Primordial Black Holes and Gravitational Wave Observations

Explores Primordial Black Holes, their formation, gravitational wave signatures, constraints on abundance, and future detection prospects.

Gravitational-Wave Transient Catalog: Insights and Challenges