Edwin Ernest Salpeter

Edwin Ernest Salpeter

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Edwin Ernest Salpeter FRS (3 December 1924, Vienna
Vienna
Vienna is the capital and largest city of the Republic of Austria and one of the nine states of Austria. Vienna is Austria's primary city, with a population of about 1.723 million , and is by far the largest city in Austria, as well as its cultural, economic, and political centre...

 – 26 November 2008, Ithaca, New York
Ithaca, New York
The city of Ithaca, is a city in upstate New York and the county seat of Tompkins County, as well as the largest community in the Ithaca-Tompkins County metropolitan area...

) was an Austrian-Australian-American astrophysicist. Born to a Jewish family, he emigrated from Austria
Austria
Austria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the...

 to Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 while in his teens to escape the Nazis. He attended Sydney University, where he obtained his bachelor's degree in 1944 and his master's degree in 1945. In the same year he was awarded an overseas scholarship and attended Birmingham University, England, where he earned his doctorate in 1948 under the supervision of Sir Rudolf Peierls
Rudolf Peierls
Sir Rudolf Ernst Peierls, CBE was a German-born British physicist. Rudolf Peierls had a major role in Britain's nuclear program, but he also had a role in many modern sciences...

. He spent the remainder of his career at Cornell University
Cornell University
Cornell University is an Ivy League university located in Ithaca, New York, United States. It is a private land-grant university, receiving annual funding from the State of New York for certain educational missions...

, where he was most recently the James Gilbert White Distinguished Professor of the Physical Sciences, Emeritus
Emeritus
Emeritus is a post-positive adjective that is used to designate a retired professor, bishop, or other professional or as a title. The female equivalent emerita is also sometimes used.-History:...

. Salpeter died of leukemia at his home in Ithaca on November 26, 2008.

In 1950 he married Miriam (Mika) Mark (1929-2000), a neurobiologist born in Riga, Latvia; she was chairwoman of the department of neurobiology and behavior at Cornell from 1982 to 1988. The Society for Neuroscience
Society for Neuroscience
The Society for Neuroscience is a professional society, headquartered in Washington, D.C., for basic scientists and physicians around the world whose research is focused on the study of the brain and nervous system.-History:...

 created the Mika Salpeter award in her memory; it "recognizes an individual with outstanding career achievements in neuroscience who has also significantly promoted the professional advancement of women in neuroscience." The Salpeters had two daughters, Judy Salpeter and Dr. Shelley Salpeter.

Scientific contributions


In 1951 Salpeter suggested that star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...

s could burn helium-4
Helium-4
Helium-4 is a non-radioactive isotope of helium. It is by far the most abundant of the two naturally occurring isotopes of helium, making up about 99.99986% of the helium on earth. Its nucleus is the same as an alpha particle, consisting of two protons and two neutrons. Alpha decay of heavy...

 into carbon-12
Carbon-12
Carbon-12 is the more abundant of the two stable isotopes of the element carbon, accounting for 98.89% of carbon; it contains 6 protons, 6 neutrons, and 6 electrons....

 with the Triple-alpha process
Triple-alpha process
The triple alpha process is a set of nuclear fusion reactions by which three helium-4 nuclei are transformed into carbon.Older stars start to accumulate helium produced by the proton–proton chain reaction and the carbon–nitrogen–oxygen cycle in their cores...

 not directly, but through an intermediate metastable state of beryllium-8, which helped to explain the carbon production in stars. He later derived the initial mass function
Initial mass function
The initial mass function is an empirical function that describes the mass distribution of a population of stars in terms of their theoretical initial mass...

 for the formation rates of stars of different mass in the Galaxy
Milky Way
The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...

.

Salpeter wrote with Hans Bethe
Hans Bethe
Hans Albrecht Bethe was a German-American nuclear physicist, and Nobel laureate in physics for his work on the theory of stellar nucleosynthesis. A versatile theoretical physicist, Bethe also made important contributions to quantum electrodynamics, nuclear physics, solid-state physics and...

 two articles in 1951 which introduced the equation bearing their names, the Bethe-Salpeter equation
Bethe-Salpeter equation
The Bethe–Salpeter equation, named after Hans Bethe and Edwin Salpeter, describes the bound states of a two-body quantum field theoretical system in a relativistically covariant formalism...

 which describes the interactions between a pair of fundamental particles
Elementary particle
In particle physics, an elementary particle or fundamental particle is a particle not known to have substructure; that is, it is not known to be made up of smaller particles. If an elementary particle truly has no substructure, then it is one of the basic building blocks of the universe from which...

 under a quantum field theory
Quantum field theory
Quantum field theory provides a theoretical framework for constructing quantum mechanical models of systems classically parametrized by an infinite number of dynamical degrees of freedom, that is, fields and many-body systems. It is the natural and quantitative language of particle physics and...

.

In 1964 Salpeter and independently Yakov B. Zel'dovich were the first to suggest that accretion disc
Accretion disc
An accretion disc is a structure formed by diffuse material in orbital motion around a central body. The central body is typically a star. Gravity causes material in the disc to spiral inward towards the central body. Gravitational forces compress the material causing the emission of...

s around massive black hole
Black hole
A black hole is a region of spacetime from which nothing, not even light, can escape. The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole. Around a black hole there is a mathematically defined surface called an event horizon that...

s are responsible for the huge amounts of energy radiated by quasars (which are the brightest active galactic nuclei
Active galactic nucleus
An active galactic nucleus is a compact region at the centre of a galaxy that has a much higher than normal luminosity over at least some portion, and possibly all, of the electromagnetic spectrum. Such excess emission has been observed in the radio, infrared, optical, ultra-violet, X-ray and...

). This is currently the most accepted explanation for the physical origin of active galactic nuclei and the associated extragalactic relativistic jet
Relativistic jet
Relativistic jets are extremely powerful jets of plasma which emerge from presumed massive objects at the centers of some active galaxies, notably radio galaxies and quasars. Their lengths can reach several thousand or even hundreds of thousands of light years...

s.

Honors

  • Carnegie Institution for Science
    Carnegie Institution for Science
    The Carnegie Institution for Science is an organization in the United States established to support scientific research....

     Award for Research in Astrophysics (1959)
  • Gold Medal of the Royal Astronomical Society
    Gold Medal of the Royal Astronomical Society
    -History:In the early years, more than one medal was often awarded in a year, but by 1833 only one medal was being awarded per year. This caused a problem when Neptune was discovered in 1846, because many felt an award should jointly be made to John Couch Adams and Urbain Le Verrier...

     (1973)
  • Henry Norris Russell Lectureship
    Henry Norris Russell Lectureship
    The Henry Norris Russell Lectureship is awarded each year by the American Astronomical Society in recognition of a lifetime of excellence in astronomical research.-Previous lecturers:This list of lecturers is from the American Astronomical Society's website....

     (1974)
  • J. Robert Oppenheimer Memorial Prize of the University of Miami
    University of Miami
    The University of Miami is a private, non-sectarian university founded in 1925 with its main campus in Coral Gables, Florida, a medical campus in Miami city proper at Civic Center, and an oceanographic research facility on Virginia Key., the university currently enrolls 15,629 students in 12...

     (1974)
  • Karl Schwarzschild Medal
    Karl Schwarzschild Medal
    The Karl Schwarzschild Medal, named after the astrophysicist Karl Schwarzschild, is an award presented by the Astronomische Gesellschaft to eminent astronomers and astrophysicists.-Recipients:...

     (1985)
  • Bruce Medal
    Bruce Medal
    The Catherine Wolfe Bruce Gold Medal is awarded every year by the Astronomical Society of the Pacific for outstanding lifetime contributions to astronomy. It is named after Catherine Wolfe Bruce, an American patroness of astronomy, and was first awarded in 1898...

     (1987)
  • Crafoord Prize
    Crafoord Prize
    The Crafoord Prize is an annual science prize established in 1980 by Holger Crafoord, a Swedish industrialist, and his wife Anna-Greta Crafoord...

     (with Fred Hoyle
    Fred Hoyle
    Sir Fred Hoyle FRS was an English astronomer and mathematician noted primarily for his contribution to the theory of stellar nucleosynthesis and his often controversial stance on other cosmological and scientific matters—in particular his rejection of the "Big Bang" theory, a term originally...

    ) (1997)

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