About stephen hawking biography entropy
Biography
It is a curious fact that Stephen William Hawking was born on 8th January 1942, exactly 300 years after the death of the Italian astronomer, Galileo Galilei. Perhaps it seems a fitting symmetry. Often referred to as ‘the father of observational astronomy,’ Galileo was one of Stephen’s inspirations during his long career as a theoretical physicist and cosmologist.
Stephen was born in Oxford during WWII, the eldest of four children to parents Dr Frank Hawking and Eileen Isobel Hawking. With his siblings, Stephen had a happy childhood mostly spent in Highgate, London and then in St. Albans, Hertfordshire. Stephen admitted to being a late developer and recalled that he was never more than halfway up the class at St Albans School. However, he developed an early curiosity as to how things work, saying later, ‘If you understand how the universe operates, you control it, in a way.’ His classmates called him ‘Einstein’ as they clearly saw the signs of genius in him, missed by his teachers. While still at school, Stephen speculated about the origin of the universe with his friends and wondered whether God created it – “I wanted to fathom the depths of the universe.” This spirit of enquiry set the pattern for his academic career.
Somewhat reluctantly, Stephen agreed to apply to his father’s college, University College, Oxford. Stephen wanted to read mathematics but his father, tropical medicine specialist Dr Frank Hawking, was adamant that there would be no jobs for mathematicians and Stephen should read medicine. They compromised on Natural Sciences and Stephen went up to Oxford at the young age of 17 in 1959. Despite claiming to do very little work, Stephen performed well enough in his written examinations to be called for a ‘viva’ (an interview) to determine which class of degree he should receive. Stephen told the examiners that if they awarded him a
Quantum Frontiers
In anticipation of The Theory of Everything which comes out today, and in the spirit of continuing with Quantum Frontiers’ current movie theme, I wanted to provide an overview of Stephen Hawking’s pathbreaking research. Or at least to the best of my ability—not every blogger on this site has won bets against Hawking! In particular, I want to describe Hawking’s work during the late ‘60s and through the ’70s. His work during the ’60s is the backdrop for this movie and his work during the ’70s revolutionized our understanding of black holes.
(Portrait of Stephen Hawking outside the Department of Applied Mathematics and Theoretical Physics, Cambridge. Credit: Jason Bye)
As additional context, this movie is coming out at a fascinating time, at a time when Hawking’s contributions appear more prescient and important than ever before. I’m alluding to the firewall paradox, which is the modern reincarnation of the information paradox (which will be discussed below), and which this blog has discussedmultiple times. Progress through paradox is an important motto in physics and Hawking has been at the center of arguably the most challenging paradox of the past half century. I should also mention that despite irresponsible journalism in response to Hawking’s “there are no black holes” comment back in January, that there is extremely solid evidence that black holes do in fact exist. Hawking was referring to a technical distinction concerning the horizon/boundary of black holes.
Now let’s jump back and imagine that we are all young graduate students at Cambridge in the early ‘60s. Our protagonist, a young Hawking, had recently been diagnosed with ALS, he had recently met Jane Wilde and he was looking for a thesis topic. This was an exciting time for Einstein’s Theory of General Relativity (GR). The gravitational redshift had recently been confirmed by Pound and Rebka at Harvard, which put the theory on extremely sol This was an equation to die for. That became clear when I turned up at Stephen Hawking’s 60th birthday celebrations in Cambridge in 2002. Reminded of his mortality by a hip-cracking collision with a wall in his motorised wheelchair a few days earlier, ‘aged 59.97’, he declared in his well-known synthesised voice: ‘I would like this simple formula to be on my tombstone.’ The year 2024 marks the 50th birthday of Hawking’s formula, which is a milestone in scientific theory and reveals a truly shocking aspect of black holes. After his death in March 2018, aged 76, the formula was engraved in stone in Westminster Abbey, and his office and its contents donated to the nation in lieu of inheritance tax. Sifting through Hawking’s personal possessions, my colleagues at the Science Museum in London have uncovered evidence of the formula’s profound influence: it featured on papers, written bets that Hawking made, mementos, even a silver beaker presented to him by the producers of the Hollywood biopic The Theory of Everything (2015). The subject of the equation, the most extraordinary of all cosmic entities, had materialised in the minds of theoreticians centuries before there was a shred of evidence that they even existed. In 1783, John Michell, a country parson in Thornhill, near Leeds, had mulled over what he called ‘dark’ stars, based on Sir Isaac Newton’s ideas, which envisaged gravity as a force and light as corpuscular, that is, consisting of particles: light particles seething from a stellar surface would have their speed reduced by the star’s gravitational pull, similar to when a bullet is fired skyward from Earth. And if a star’s gravity were sufficiently strong, Michell realised that the light would fall back to the surface. Though this captured the gist of a black hole, Michell was wrong in key respects: general relativity, Albert Einst The Bekenstein-Hawking entropy or black hole entropy is the amount of entropy that must be assigned to a black hole in order for it to comply with the laws of thermodynamics as they are interpreted by observers external to that black hole. This is particularly true for the first and second laws. Black hole entropy is a concept with geometric root but with many physical consequences. It ties together notions from gravitation, thermodynamics and quantum theory, and is thus regarded as a window into the as yet mostly hidden world of quantum gravity. A black hole may be described as a blemish in spacetime, or a locale of very high curvature. Is it meaningful or desirable to associate entropy with it ? Is this possible at all ? There are several ways to justify the concept of black hole entropy (Bekenstein 1972, 1973). Stephen Hawking’s greatest legacy – a simple little equation now 50 years old – revealed a shocking aspect of black holes
Bekenstein-Hawking entropy
Why black hole entropy?