The Big Bang is a physical theory that describes how the universe expanded from an initial state of high density and temperature. The notion of an expanding universe was first scientifically originated by physicist Alexander Friedmann in 1922 with the mathematical derivation of the Friedmann equations. The earliest empirical observation of the notion of an expanding universe is known as Hubble's Law, published in work by physicist Edwin Hubble in 1929, which discerned that galaxies are moving away from Earth at a rate that accelerates proportionally with distance. Independent of Friedmann's work, and independent of Hubble's observations, physicist Georges Lemaître proposed that the universe emerged from a "primeval atom" in 1931, introducing the modern notion of the Big Bang.
A black hole is a region of spacetime wherein gravity is so strong that no matter or electromagnetic energy can escape it. Albert Einstein's theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole. The boundary of no escape is called the event horizon. A black hole has a great effect on the fate and circumstances of an object crossing it, but it has no locally detectable features according to general relativity. In many ways, a black hole acts like an ideal black body, as it reflects no light. Quantum field theory in curved spacetime predicts that event horizons emit Hawking radiation, with the same spectrum as a black body of a temperature inversely proportional to its mass. This temperature is of the order of billionths of a kelvin for stellar black holes, making it essentially impossible to observe directly.
Sir Roger Penrose is a British mathematician, mathematical physicist, philosopher of science and Nobel Laureate in Physics. He is Emeritus Rouse Ball Professor of Mathematics in the University of Oxford, an emeritus fellow of Wadham College, Oxford, and an honorary fellow of St John's College, Cambridge, and University College London.
The following is a timeline of gravitational physics and general relativity.
Timeline of black hole physics
A Brief History of Time: From the Big Bang to Black Holes is a book on theoretical cosmology by the physicist Stephen Hawking. It was first published in 1988. Hawking wrote the book for readers who had no prior knowledge of physics.
The Laser Interferometer Gravitational-Wave Observatory (LIGO) is a large-scale physics experiment and observatory designed to detect cosmic gravitational waves and to develop gravitational-wave observations as an astronomical tool. Two large observatories were built in the United States with the aim of detecting gravitational waves by laser interferometry. These observatories use mirrors spaced four kilometers apart to measure changes in length—over an effective span of 1120 km—of less than one ten-thousandth the charge diameter of a proton.
Fellowship of the Royal Society is an award granted by the Fellows of the Royal Society of London to individuals who have made a "substantial contribution to the improvement of natural knowledge, including mathematics, engineering science, and medical science".
Martin John Rees, Baron Rees of Ludlow, is a British cosmologist and astrophysicist. He is the fifteenth Astronomer Royal, appointed in 1995, and was Master of Trinity College, Cambridge, from 2004 to 2012 and President of the Royal Society between 2005 and 2010. He has received various physics awards including the Wolf Prize in Physics in 2024 for fundamental contributions to high-energy astrophysics, galaxies and structure formation, and cosmology.
The Royal Society Science Books Prize is an annual £25,000 prize awarded by the Royal Society to celebrate outstanding popular science books from around the world. It is open to authors of science books written for a non-specialist audience, and since it was established in 1988 has championed writers such as Stephen Hawking, Jared Diamond, Stephen Jay Gould and Bill Bryson. In 2015 The Guardian described the prize as "the most prestigious science book prize in Britain".
Sir Ian Wilmut was a British embryologist and the chair of the Scottish Centre for Regenerative Medicine at the University of Edinburgh. He is best known as the leader of the research group that in 1996 first cloned a mammal from an adult somatic cell, a Finnish Dorset lamb named Dolly.
Leonard Mlodinow is an American theoretical physicist and mathematician, screenwriter and author. In physics, he is known for his work on the large N expansion, a method of approximating the spectrum of atoms based on the consideration of an infinite-dimensional version of the problem, and for his work on the quantum theory of light inside dielectrics.
Werner Israel, was a theoretical physicist known for his contributions to gravitational theory, and especially to the understanding of black holes.
Gravitational waves are transient displacements in a gravitational field – generated by the relative motion of gravitating masses – that radiate 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 the gravitational equivalent of electromagnetic waves. In 1916, Albert Einstein demonstrated that gravitational waves result from his general theory of relativity as ripples in spacetime.
The following outline is provided as an overview of and topical guide to black holes:
Bernard F. Schutz FInstP FLSW is an American and naturalised British physicist. He is well known for his research in Einstein's theory of general relativity, especially for his contributions to the detection of gravitational waves, and for his textbooks. Schutz is a Fellow of the Royal Society and a Member of the US National Academy of Sciences. He is a professor of physics and astronomy at Cardiff University, and was a founding director of the Max Planck Institute for Gravitational Physics in Potsdam, Germany, where he led the Astrophysical Relativity division from 1995 to 2014. Schutz was a founder and principal investigator of the GEO gravitational wave collaboration, which became part of the LIGO Scientific Collaboration (LSC). Schutz was also one of the initiators of the proposal for the space-borne gravitational wave detector LISA, and he coordinated the European planning for its data analysis until the mission was adopted by ESA in 2016. Schutz conceived and in 1998 began publishing from the AEI the online open access (OA) review journal Living Reviews in Relativity, which for many years has been the highest-impact OA journal in the world, as measured by Clarivate.
Stephen William Hawking was an English theoretical physicist, cosmologist, and author who was director of research at the Centre for Theoretical Cosmology at the University of Cambridge. Between 1979 and 2009, he was the Lucasian Professor of Mathematics at Cambridge, widely viewed as one of the most prestigious academic posts in the world.
GW170817 was a gravitational wave (GW) signal observed by the LIGO and Virgo detectors on 17 August 2017, originating from the shell elliptical galaxy NGC 4993, about 140 million light years away. The signal was produced by the last moments of the inspiral process of a binary pair of neutron stars, ending with their merger. It was the first GW observation to be confirmed by non-gravitational means. Unlike the five previous GW detections—which were of merging black holes and thus not expected to produce a detectable electromagnetic signal—the aftermath of this merger was seen across the electromagnetic spectrum by 70 observatories on 7 continents and in space, marking a significant breakthrough for multi-messenger astronomy. The discovery and subsequent observations of GW170817 were given the Breakthrough of the Year award for 2017 by the journal Science.
Time's Arrow and Archimedes Point: New Directions for the Physics of Time is a 1996 book by Huw Price, on the physics and philosophy of the Arrow of Time. It explores the problem of the direction of time, looking at issues in thermodynamics, cosmology, electromagnetism, and quantum mechanics. Price argues that it is fruitful to think about time from a hypothetical Archimedean Point - a viewpoint outside of time. In later chapters, Price argues that retrocausality can resolve many of the philosophical issues facing quantum mechanics and along these lines proposes an interpretation involving what he calls 'advanced action'.
