James Lighthill
Encyclopedia
Sir Michael James Lighthill, FRS
(23 January 1924 – 17 July 1998) was a British
applied mathematician
, known for his pioneering work in the field of aeroacoustics
.
, and worked at the National Physical Laboratory
, Trinity College, Cambridge
and between 1946 and 1959 at the University of Manchester
where he held the Beyer Chair
. Lighthill then moved from Manchester to become director of the Royal Aircraft Establishment
at Farnborough
. There he worked on the development of television and communications satellites, and on the development of manned spacecraft
. This latter work was used in the development of the Concorde
supersonic airliner
.
In 1955, together with G. B. Whitham
, Lighthill set out the first comprehensive theory of kinematic waves (an application of the method of characteristics
), with a multitude of applications, prime among them fluid flow and traffic flow.
Lighthill's early work included two dimensional aerofoil
theory, and supersonic
flow around solids of revolution
. In addition to the dynamics of gas at high speeds he studied shock and blast waves. He is credited with founding the subject of aeroacoustics, a subject vital to the reduction of noise in jet engine
s. Lighthill's eighth power law states that the acoustic power radiated by a jet engine is proportional to the eighth power
of the jet speed. He also founded non-linear
acoustics, and showed that the same non-linear differential equation
s could model both flood waves in rivers and traffic flow in highways.
In 1964 he became the Royal Society
's resident professor at Imperial College London
, before returning to Trinity College, Cambridge, five years later as Lucasian Professor of Mathematics, a chair he held until 1979, when he was succeeded by Stephen Hawking
. Lighthill then became Provost
of University College London
(UCL) — a post he held until 1989.
Lighthill founded the Institute of Mathematics and its Applications
in 1964.
In the early 1970s, partly in reaction to significant internal discord within that field, the Science Research Council (SRC)
, as it was then known, asked Lighthill to compile a review of academic research in Artificial Intelligence
. Lighthill's report, which was published in 1973 and became known as the "Lighthill report
," was highly critical of basic research in foundational areas such as robotics
and language processing
, and "formed the basis for the decision by the British government to end support for AI research in all but two universities", starting what is sometimes referred to as the "AI winter
."
His hobby was open-water swimming. He died in the water in 1998 when the mitral valve
in his heart ruptured while swimming round the island of Sark
, a feat which he had accomplished many times before.
Royal Society
The Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...
(23 January 1924 – 17 July 1998) was a British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
applied mathematician
Applied mathematics
Applied mathematics is a branch of mathematics that concerns itself with mathematical methods that are typically used in science, engineering, business, and industry. Thus, "applied mathematics" is a mathematical science with specialized knowledge...
, known for his pioneering work in the field of aeroacoustics
Aeroacoustics
Aeroacoustics is a branch of acoustics that studies noise generation via either turbulent fluid motion or aerodynamic forces interacting with surfaces. Noise generation can also be associated with periodically varying flows...
.
Biography
Lighthill specialised in fluid dynamicsFluid dynamics
In physics, fluid dynamics is a sub-discipline of fluid mechanics that deals with fluid flow—the natural science of fluids in motion. It has several subdisciplines itself, including aerodynamics and hydrodynamics...
, and worked at the National Physical Laboratory
National Physical Laboratory, UK
The National Physical Laboratory is the national measurement standards laboratory for the United Kingdom, based at Bushy Park in Teddington, London, England. It is the largest applied physics organisation in the UK.-Description:...
, Trinity College, Cambridge
Trinity College, Cambridge
Trinity College is a constituent college of the University of Cambridge. Trinity has more members than any other college in Cambridge or Oxford, with around 700 undergraduates, 430 graduates, and over 170 Fellows...
and between 1946 and 1959 at the University of Manchester
University of Manchester
The University of Manchester is a public research university located in Manchester, United Kingdom. It is a "red brick" university and a member of the Russell Group of research-intensive British universities and the N8 Group...
where he held the Beyer Chair
Beyer Chair of Applied Mathematics
The Beyer Chair of Applied Mathematics is an endowed professorial position in the School of Mathematics, University of Manchester, England. The endowment came from the engineer Charles Frederick Beyer, a generous supporter of the University....
. Lighthill then moved from Manchester to become director of the Royal Aircraft Establishment
Royal Aircraft Establishment
The Royal Aircraft Establishment , was a British research establishment, known by several different names during its history, that eventually came under the aegis of the UK Ministry of Defence , before finally losing its identity in mergers with other institutions.The first site was at Farnborough...
at Farnborough
Farnborough, Hampshire
-History:Name changes: Ferneberga ; Farnburghe, Farenberg ; Farnborowe, Fremborough, Fameborough .Tower Hill, Cove: There is substantial evidence...
. There he worked on the development of television and communications satellites, and on the development of manned spacecraft
Spacecraft
A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....
. This latter work was used in the development of the Concorde
Concorde
Aérospatiale-BAC Concorde was a turbojet-powered supersonic passenger airliner, a supersonic transport . It was a product of an Anglo-French government treaty, combining the manufacturing efforts of Aérospatiale and the British Aircraft Corporation...
supersonic airliner
Airliner
An airliner is a large fixed-wing aircraft for transporting passengers and cargo. Such aircraft are operated by airlines. Although the definition of an airliner can vary from country to country, an airliner is typically defined as an aircraft intended for carrying multiple passengers in commercial...
.
In 1955, together with G. B. Whitham
Gerald B. Whitham
Gerald Beresford Whitham is an American applied mathematician and the Charles Lee Powell Professor of Applied Mathematics of Applied & Computational Mathematics at the California Institute of Technology. He received his Ph.D. from the University of Manchester in 1953 under the direction of Sir...
, Lighthill set out the first comprehensive theory of kinematic waves (an application of the method of characteristics
Method of characteristics
In mathematics, the method of characteristics is a technique for solving partial differential equations. Typically, it applies to first-order equations, although more generally the method of characteristics is valid for any hyperbolic partial differential equation...
), with a multitude of applications, prime among them fluid flow and traffic flow.
Lighthill's early work included two dimensional aerofoil
Airfoil
An airfoil or aerofoil is the shape of a wing or blade or sail as seen in cross-section....
theory, and supersonic
Supersonic
Supersonic speed is a rate of travel of an object that exceeds the speed of sound . For objects traveling in dry air of a temperature of 20 °C this speed is approximately 343 m/s, 1,125 ft/s, 768 mph or 1,235 km/h. Speeds greater than five times the speed of sound are often...
flow around solids of revolution
Solid of revolution
In mathematics, engineering, and manufacturing, a solid of revolution is a solid figure obtained by rotating a plane curve around some straight line that lies on the same plane....
. In addition to the dynamics of gas at high speeds he studied shock and blast waves. He is credited with founding the subject of aeroacoustics, a subject vital to the reduction of noise in jet engine
Jet engine
A jet engine is a reaction engine that discharges a fast moving jet to generate thrust by jet propulsion and in accordance with Newton's laws of motion. This broad definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets...
s. Lighthill's eighth power law states that the acoustic power radiated by a jet engine is proportional to the eighth power
Exponentiation
Exponentiation is a mathematical operation, written as an, involving two numbers, the base a and the exponent n...
of the jet speed. He also founded non-linear
Nonlinearity
In mathematics, a nonlinear system is one that does not satisfy the superposition principle, or one whose output is not directly proportional to its input; a linear system fulfills these conditions. In other words, a nonlinear system is any problem where the variable to be solved for cannot be...
acoustics, and showed that the same non-linear differential equation
Differential equation
A differential equation is a mathematical equation for an unknown function of one or several variables that relates the values of the function itself and its derivatives of various orders...
s could model both flood waves in rivers and traffic flow in highways.
In 1964 he became the Royal Society
Royal Society
The Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...
's resident professor at Imperial College London
Imperial College London
Imperial College London is a public research university located in London, United Kingdom, specialising in science, engineering, business and medicine...
, before returning to Trinity College, Cambridge, five years later as Lucasian Professor of Mathematics, a chair he held until 1979, when he was succeeded by Stephen Hawking
Stephen Hawking
Stephen William Hawking, CH, CBE, FRS, FRSA is an English theoretical physicist and cosmologist, whose scientific books and public appearances have made him an academic celebrity...
. Lighthill then became Provost
Provost (education)
A provost is the senior academic administrator at many institutions of higher education in the United States, Canada and Australia, the equivalent of a pro-vice-chancellor at some institutions in the United Kingdom and Ireland....
of University College London
University College London
University College London is a public research university located in London, United Kingdom and the oldest and largest constituent college of the federal University of London...
(UCL) — a post he held until 1989.
Lighthill founded the Institute of Mathematics and its Applications
Institute of Mathematics and its Applications
The Institute of Mathematics and its Applications is the UK's chartered professional body for mathematicians and one of the UK's learned societies for mathematics ....
in 1964.
In the early 1970s, partly in reaction to significant internal discord within that field, the Science Research Council (SRC)
Science and Engineering Research Council
The Science and Engineering Research Council used to be the UK agency in charge of publicly funded scientific and engineering research activities including astronomy, biotechnology and biological sciences, space research and particle physics...
, as it was then known, asked Lighthill to compile a review of academic research in Artificial Intelligence
Artificial intelligence
Artificial intelligence is the intelligence of machines and the branch of computer science that aims to create it. AI textbooks define the field as "the study and design of intelligent agents" where an intelligent agent is a system that perceives its environment and takes actions that maximize its...
. Lighthill's report, which was published in 1973 and became known as the "Lighthill report
Lighthill report
The Lighthill report is the name commonly used for the paper "Artificial Intelligence: A General Survey" by James Lighthill, published in Artificial Intelligence: a paper symposium in 1973....
," was highly critical of basic research in foundational areas such as robotics
Robotics
Robotics is the branch of technology that deals with the design, construction, operation, structural disposition, manufacture and application of robots...
and language processing
Language processing
Language processing refers to the way human beings process speech or writing and understand it as language. Most recent theories back the idea that this process is made completely by and inside the brain.- Spoken language :...
, and "formed the basis for the decision by the British government to end support for AI research in all but two universities", starting what is sometimes referred to as the "AI winter
AI winter
In the history of artificial intelligence, an AI winter is a period of reduced funding and interest in artificial intelligence research. The process of hype, disappointment and funding cuts are common in many emerging technologies , but the problem has been particularly acute for AI...
."
His hobby was open-water swimming. He died in the water in 1998 when the mitral valve
Mitral valve
The mitral valve is a dual-flap valve in the heart that lies between the left atrium and the left ventricle...
in his heart ruptured while swimming round the island of Sark
Sark
Sark is a small island in the Channel Islands in southwestern English Channel, off the French coast of Normandy. It is a royal fief, geographically located in the Channel Islands in the Bailiwick of Guernsey, with its own set of laws based on Norman law and its own parliament. It has a population...
, a feat which he had accomplished many times before.