Physics Evolution - Text Only Version

1922 to 2000

The Physics revolutions of the beginning of the century laid the foundations for the age of information and communication technology. However, even now, the two big theories of Quantum Mechanics (for the very small) and Relativity (for the enormous) remain unreconciled. Physics is still moving on.

Hideki Yukawa, physicist – Forces and particles (1907-1981)

Physicist born in Tokyo

Hideki Yukawa did extensive research in quantum mechanics. In 1935, together with Ernest Stueckelberg, he predicted the existence of an elementary particle – the meson – with a mass about 200 times that of the electron, now called the pion.

The existence of the pion was proved in 1947.

Sir Fred Hoyle, cosmologist – Gave us the ‘Big Bang’ – a theory he reviled (1915- 2001)

Astrophysicist and cosmologist, born at Bingley, in Yorkshire.

Fred Hoyle was born in Yorkshire and took an early interest in stars to which he returned having studied mathematics for his degree.

He was absolutely opposed to the idea that the Universe had a beginning – “Every cluster of galaxies, every star, every atom had a beginning, but the universe itself did not”. He argued for the steady state model and coined the term Big Bang to deride the opposition.

Edward Lorenz, meteorologist – Butterfly effect and chaos (1917 -)

Research meteorologist, MIT, Chicago

Edward Lorenz discovered the branch of mathematics known as Chaos. This deals with non-linear, sensitive systems that appear to be random but are driven by simple rules.

He was working on weather prediction during the 1960s using a basic computer to simulate weather patterns. He wanted to rerun some data and re-entered some values but to 3 significant figures instead of the 5 previously used. Although this was a tiny difference, to his surprise, the weather that the computer predicted was completely different.

He had discovered the Butterfly Effect – a classic example of chaos, where small changes in initial conditions produce large changes in the long-term outcome.

Benoit Mandelbrot, mathematician – A new geometry – fractals (1924- )

French/American mathematician born in Warsaw, Poland.

Benoit Mandelbrot developed fractal geometry as a method of dealing with the many complicated shapes and forms that exist in nature.

Fractals are geometric shapes that are very complex and infinitely detailed. You can zoom in on a section and it will have just as much detail as the whole fractal. His book The Fractal Geometry of Nature contains many examples of natural fractals such as ferns, trees, mountains and river basins.

He showed that fractals could be used as models of many natural phenomena, including the shape of coastlines, clouds, the clustering of galaxies and even stock market prices. Far from being unnatural, Mandelbrot held the view that fractals were, in many ways, more intuitive and natural than the artificially smooth objects of traditional Euclidean geometry.

His ideas sparked widespread popular interest in fractals as well as contributing to new fields of science such as the study of chaos.

Stephen Hawking, physicist – Star of The Simpsons (twice) (1942- )

Theoretical physicist and cosmologist born in Oxford, England.

Stephen Hawking is probably the best known living Physicist – partly through his book A Brief History of Time and partly through his cartoon appearance on The Simpsons.

Hawking’s main Physics work has been to the theory of black holes and to the Big Bang Theory.

His first important paper was written with Roger Penrose in the mid 1960s. It predicted that the expanding Universe must have been born from a singularity – a mathematical point of zero volume where the laws of Physics cease.

At the time of the Big Bang, the singularity would have exploded and the Universe would have come into being. Space, time, and energy would have been created and would have expanded together.

In 1988 he published the best-seller “A brief history of time”, an introduction to quantum physics and relativity.

He has motor neurone disease and his physical condition has deteriorated so much that he is confined to a wheelchair and can communicate only by using one finger to move the cursor on the screen of a computer linked to a voice synthesizer.

Sir Roger Penrose, mathematical physicist – Geometry, Black Holes and consciousness (1931- )

Mathematical physicist, born in Colchester, Essex, England

Roger Penrose is known for his research in geometry, relativity, quantum mechanics and the theory of consciousness.

In 1965, Penrose showed that very massive stars could collapse in on themselves, and form objects called black holes.

At the centre of a black hole, there would be an object with an infinite density and zero size, called a singularity – a mathematical point of zero volume where the laws of Physics cease. As bizarre as they sound, singularities are not disallowed by the General Theory of Relativity.

Penrose has criticized the notion that human thinking is basically the same as the action of a very complicated computer.

His ideas on consciousness, put forward in his books The Emperor’s New Mind and Shadows of the Mind are controversial and have attracted some hostile criticism.

Murray Gell-Mann, American physicist – The ‘man with five brains’ (1929- )

Physicist, born in New York.

Murray Gell-Mann, or the ‘man with five brains’, as he has been called, has given us the eightfold way, the word quark and some confusion over its origin.

Gell-Mann was born in New York at the start of the Great depression. His father was an Austrian immigrant and strongly influenced the young Murray, who was teaching himself calculus when he was seven. He went to Yale at 15 and, as a compromise with his father, took Physics.

When he was 20 and now at MIT, he solved a problem of particle decay by introducing a new quantity called strangeness. From this he developed the eightfold way as a means of classifying subatomic particles and predicted the existence of the omega-minus – which was duly found.

To explain the plethora of new particles that were being discovered, Gell-Mann proposed a family of fundamental particles that he called ‘quarks’ (to rhyme with ‘walks’). He did not, as some suggest, lift the word from Finnegan’s Wake (in which it rhymes with ‘park’).

He has wide ranging interests (hence the “five brains” tag) including the connection between simplicity and complexity, the subjects of his popular book The Quark and the Jaguar.

John Bardeen, physicist – Who came up with the name ‘gluon’?! (1908 to 1991)

Physicist born in Madison, Wisconsin

John Bardeen is the only person to have won two Nobel prizes in Physics.

In 1947, Bardeen, Shockley, and Brattain, working in Bell Labs on long distance telephone communication, invented the transistor. They were awarded the Nobel Prize for the invention in 1956. Without transistors, there would have been no computers, portable radios or televisions.

In 1972, Bardeen was awarded his second Nobel Prize, together with Leon Cooper and John Schrieffer for their theory of superconductivity, now called BCS theory.

With Gell-Mann and Fritsch, Bardeen developed Quantum Chromodynamics in 1972. This is a theory describing (in terms of gluons) the strong nuclear force between quarks.

Abdus Salam, physicist – Started a nuclear weapons programme (1926-1996)

Physicist, born in Jhang Sadar Pakistan

Abdus Salam achieved the first unification of forces since Maxwell brought together electricity and magnetism in the 19th century.

In Salam’s case, it was the electromagnetic and the weak forces that he unified into the electroweak force. Steven Weinberg independently proposed a similar theory at the same time and they shared the 1979 Nobel Prize along with Sheldon Glashow.

The theory has been a success in that it predicted the existence of W and Z bosons which have since been found at CERN.

In the early 1970s, Salam played a role in starting Pakistan’s nuclear weapons program.

Alexei Starobinsky, physicist – Inflationary theory from behind the Iron Curtain (1950 – )

Theoretical physicist from The Landau Institute, Moscow

Starobinsky developed the first inflationary model of the Universe at the end of the 1970s – but it was not then called ‘inflation’. This model describes the rapid expansion of the Universe (from the size of a proton to the size of a grapefruit) almost immediately after it was created in the Big Bang.

It was a very complicated model based on a quantum theory of gravity, but it caused a sensation among cosmologists in what was then the Soviet Union, becoming known as the ‘Starobinsky model’.

Unfortunately, because of the difficulties Soviet scientists still had in travelling abroad or communicating with colleagues outside, the news did not spread outside their country.

Alan Guth, American physicist and cosmologist – Inflationary theory (1947 -)

Physicist and cosmologist from MIT, Chicago

Guth researched elementary particle theory (and how particle theory is applicable to the early universe).

In 1980 Guth, not knowing anything of Starobinsky’s work, proposed a different version of the Inflationary Theory based on the work of physicists such as Stephen Hawking. Inflation describes the rapid expansion of the Universe (from the size of a proton to the size of a grapefruit) almost immediately after it was created.

His theory explained how the Big Bang could produce a Universe that would eventually stop expanding and would also produce uniform microwave background radiation.

Sir Tim Berners-Lee, physicist – Developed http and invented the World Wide Web (1955 -)

Physicist and computer scientist

Tim Berners-Lee was born in London in 1955. He studied Physics at Oxford, where he was banned from using the University’s computers after he hacked into the network. He is now best known for inventing the World Wide Web and for giving it to the world for free.

After graduating, Berners-Lee worked as a computer programmer and took a temporary job at CERN (see below) in the mid 1980s. He worked on an information system that used hypertext links to navigate between entries and show connections between them.

At that time, most Universities, research organisations and technology companies had their own computer networks; and there were links between these networks – the internet. Berners-Lee proposed a generalised method of sharing information between these networks over the internet.

Although his proposal wasn’t picked up, in 1990, he wrote the code that would allow networks to access and share hypertext documents over the internet – hypertext transfer protocol (http). He also wrote a programme to view these documents, a browser that he called WorldWideWeb and posted the world’s first web page.

He posted his programmes on internet newsgroups and they quickly became popular – particularly amongst scientists for sharing information over the internet. He did not patent the technology and was aware that big software companies might try to control what he felt should be an open and free system. In 1994, after a conference at CERN, the World Wide Web Consortium (W3C), headed by Berners-Lee, was set up to “lead the web to its full potential”.

CERN is the world’s biggest particle physics laboratory and houses particle accelerators that are among the largest scientific instruments ever built. In these devices, elementary particles are accelerated to tremendously high energies and then smashed together. These collisions, recorded by particle detectors, give a glimpse of matter as it was moments after the Big Bang. Work in the bubble chamber at CERN has provided evidence for the existence of quarks – first predicted by Gell-Mann in 1963.