Edwin Ernest Salpeter (3 December 1924 – 26 November 2008,) was an Austrian–Australian–American astrophysicist.

Life

Born in

Vienna Vienna ( ; ; ) is the capital city, capital, List of largest cities in Austria, most populous city, and one of Federal states of Austria, nine federal states of Austria. It is Austria's primate city, with just over two million inhabitants. ...

to a Jewish family, Salpeter emigrated from Austria to Australia while in his teens to escape the Nazis. He attended

Sydney Boys High School Sydney Boys High School ('SBHS'), otherwise known as Sydney High School ('SHS') or simply High, is an Australian government-funded single-sex academically selective secondary day school for boys, located at Moore Park, New South Wales, a s ...

(1939–40) and

Sydney University The University of Sydney (USYD) is a public university, public research university in Sydney, Australia. Founded in 1850, it is the oldest university in both Australia and Oceania. One of Australia's six sandstone universities, it was one of the ...

, 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 the

University of Birmingham The University of Birmingham (informally Birmingham University) is a Public university, public research university in Birmingham, England. It received its royal charter in 1900 as a successor to Queen's College, Birmingham (founded in 1825 as ...

, England, where he earned his doctorate in 1948 under the supervision of Sir

Rudolf Peierls Sir Rudolf Ernst Peierls, (; ; 5 June 1907 – 19 September 1995) was a German-born British physicist who played a major role in Tube Alloys, Britain's nuclear weapon programme, as well as the subsequent Manhattan Project, the combined Allied ...

. He spent the remainder of his career at

Cornell University Cornell University is a Private university, private Ivy League research university based in Ithaca, New York, United States. The university was co-founded by American philanthropist Ezra Cornell and historian and educator Andrew Dickson W ...

, where he was the James Gilbert White Distinguished Professor of the Physical Sciences. Salpeter died of leukemia at his home in

Ithaca, New York Ithaca () is a city in and the county seat of Tompkins County, New York, United States. Situated on the southern shore of Cayuga Lake in the Finger Lakes region of New York (state), New York, Ithaca is the largest community in the Ithaca metrop ...

on 26 November 2008.

Scientific contributions

In 1951 Salpeter suggested that stars could burn

helium-4 Helium-4 () is a stable isotope of the element helium. It is by far the more abundant of the two naturally occurring isotopes of helium, making up about 99.99986% of the helium on Earth. Its nucleus is identical to an alpha particle, and consi ...

into

carbon-12 Carbon-12 (12C) is the most abundant of the two stable isotopes of carbon ( carbon-13 being the other), amounting to 98.93% of element carbon on Earth; its abundance is due to the triple-alpha process by which it is created in stars. Carbon-1 ...

with the

Triple-alpha process The triple-alpha process is a set of nuclear fusion reactions by which three helium-4 nuclei (alpha particles) are transformed into carbon. In stars Helium accumulates in the cores of stars as a result of the proton–proton chain reaction a ...

not directly, but through an intermediate metastable state of

beryllium-8 Beryllium-8 (8Be, Be-8) is a radionuclide with 4 neutrons and 4 protons. It is an unbound resonance and nominally an isotope of beryllium. It has a half-life on the order of 8.19 seconds, decaying into two alpha particles. This has importa ...

, which helped to explain the carbon production in stars. He later derived the

initial mass function In astronomy, the initial mass function (IMF) is an empirical function that describes the initial distribution of masses for a population of stars during star formation. IMF not only describes the formation and evolution of individual stars, it a ...

for the formation rates of stars of different mass in the

Galaxy A galaxy is a Physical system, system of stars, stellar remnants, interstellar medium, interstellar gas, cosmic dust, dust, and dark matter bound together by gravity. The word is derived from the Ancient Greek, Greek ' (), literally 'milky', ...

. Salpeter wrote with

Hans Bethe Hans Albrecht Eduard Bethe (; ; July 2, 1906 – March 6, 2005) was a German-American physicist who made major contributions to nuclear physics, astrophysics, quantum electrodynamics and solid-state physics, and received the Nobel Prize in Physi ...

two articles in 1951 which introduced the equation bearing their names, the Bethe–Salpeter equation which describes the interactions between a pair of

fundamental particles In particle physics, an elementary particle or fundamental particle is a subatomic particle that is not composed of other particles. The Standard Model presently recognizes seventeen distinct particles—twelve fermions and five bosons. As a con ...

under a

quantum field theory In theoretical physics, quantum field theory (QFT) is a theoretical framework that combines Field theory (physics), field theory and the principle of relativity with ideas behind quantum mechanics. QFT is used in particle physics to construct phy ...

. In 1955 he found the Salpeter function or the

(IMF). It shows that the number of stars in each mass range decreases rapidly with increasing mass. In 1964 Salpeter and independently Yakov B. Zel'dovich were the first to suggest that

accretion disc An accretion disk is a structure (often a circumstellar disk) formed by diffuse material in orbital motion around a massive central body. The central body is most frequently a star. Friction, uneven irradiance, magnetohydrodynamic effects, and ...

s around massive

black hole A black hole is a massive, compact astronomical object so dense that its gravity prevents anything from escaping, even light. Albert Einstein's theory of general relativity predicts that a sufficiently compact mass will form a black hole. Th ...

s are responsible for the huge amounts of energy radiated by

quasar A quasar ( ) is an extremely Luminosity, luminous active galactic nucleus (AGN). It is sometimes known as a quasi-stellar object, abbreviated QSO. The emission from an AGN is powered by accretion onto a supermassive black hole with a mass rangi ...

s (which are the brightest

active galactic nuclei An active galactic nucleus (AGN) is a compact region at the center of a galaxy that emits a significant amount of energy across the electromagnetic spectrum, with characteristics indicating that this luminosity is not produced by the stars. Such e ...

). This is currently the most accepted explanation for the physical origin of active galactic nuclei and the associated extragalactic

relativistic jet An astrophysical jet is an astronomical phenomenon where outflows of ionised matter are emitted as extended beams along the axis of rotation. When this greatly accelerated matter in the beam approaches the speed of light, astrophysical jets becom ...

s. In early 1970s, Salpeter discovered that molecular hydrogen and many other molecular species are formed in the interstellar medium not as much in the gas phase but primarily on the surfaces of dust particles.

Family

In 1950 he married Miriam (Mika) Mark (1929–2000), a

neurobiologist A neuroscientist (or neurobiologist) is a scientist specializing in neuroscience that deals with the anatomy and function of neurons, neural circuits, and glia, and their behavioral, biological, and psychological roles in health and disease. ...

born in

Riga Riga ( ) is the capital, Primate city, primate, and List of cities and towns in Latvia, largest city of Latvia. Home to 591,882 inhabitants (as of 2025), the city accounts for a third of Latvia's total population. The population of Riga Planni ...

Latvia Latvia, officially the Republic of Latvia, is a country in the Baltic region of Northern Europe. It is one of the three Baltic states, along with Estonia to the north and Lithuania to the south. It borders Russia to the east and Belarus to t ...

; she was chairwoman of the department of neurobiology and behavior at Cornell from 1982 to 1988. The

Society for Neuroscience The Society for Neuroscience (SfN) 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. It is especially well k ...

created the Mika Salpeter award in her memory; it "recognizes an individual with outstanding career achievements in

neuroscience Neuroscience is the scientific study of the nervous system (the brain, spinal cord, and peripheral nervous system), its functions, and its disorders. It is a multidisciplinary science that combines physiology, anatomy, molecular biology, ...

who has also significantly promoted the professional advancement of women in neuroscience." The Salpeters had two daughters, Judy Salpeter and Dr. Shelley Salpeter. After Miriam's death, Edwin married Antonia Shouse.

Honors

Carnegie Institution for Science The Carnegie Institution for Science, also known as Carnegie Science and the Carnegie Institution of Washington, is an organization established to fund and perform scientific research in the United States. This institution is headquartered in W ...

Award for Research in Astrophysics (1959) *Member of the

American Academy of Arts and Sciences The American Academy of Arts and Sciences (The Academy) is one of the oldest learned societies in the United States. It was founded in 1780 during the American Revolution by John Adams, John Hancock, James Bowdoin, Andrew Oliver, and other ...

(1967) *Member of the United States

National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, NGO, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the ...

(1967) *

Gold Medal of the Royal Astronomical Society The Gold Medal of the Royal Astronomical Society is the highest award given by the Royal Astronomical Society (RAS). The RAS Council have "complete freedom as to the grounds on which it is awarded" and it can be awarded for any reason. Past awar ...

(1973) *

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. The idea for the lectureship came from then society President Harlow Shapley in 1945, ...

(1974) *

J. Robert Oppenheimer Memorial Prize The J. Robert Oppenheimer Memorial Prize and Medal was awarded by the Center for Theoretical Studies, University of Miami, from 1969, until 1984. Established in memory of US physicist J. Robert Oppenheimer, the award consisted of a medal, certifi ...

(1974) *Member of the

American Philosophical Society The American Philosophical Society (APS) is an American scholarly organization and learned society founded in 1743 in Philadelphia that promotes knowledge in the humanities and natural sciences through research, professional meetings, publicat ...

(1977) *

Karl Schwarzschild Medal The Karl Schwarzschild Medal, named after the astrophysicist Karl Schwarzschild, is an award presented by the Astronomische Gesellschaft (German Astronomical Society) to eminent astronomers and astrophysicists. Recipients SourceGerman Astronomical ...

(1985) *

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 ...

(1987) *

Dirac Medal The Dirac Medal or Dirac prize can refer to different awards named in honour of the physics Nobel Laureate Paul Dirac. * Dirac Medal (ICTP), awarded by the Abdus Salam International Centre for Theoretical Physics, Trieste * Dirac Medal (IOP), awar ...

of the

University of South Wales The University of South Wales (USW) () is a public university in Wales, with campuses in Cardiff, Newport and Pontypridd. It was formed on 11 April 2013 from the merger of the University of Glamorgan and the University of Wales, Newport. The ...

(1996) *

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 following a donation to the Royal Swedish Academy of Sciences. It is awarded jointly by the Acade ...

(with

Fred Hoyle Sir Fred Hoyle (24 June 1915 – 20 August 2001) was an English astronomer who formulated the theory of stellar nucleosynthesis and was one of the authors of the influential B2FH paper, B2FH paper. He also held controversial stances on oth ...

) (1997) * Hans Bethe Prize (1999)

References

External links

Bruce Medal page

bio page

Oral History interview transcript with Edwin Ernest Salpeter on 30 March 1978, American Institute of Physics, Niels Bohr Library & Archives
- interview conducted by Spencer Weart at Newman Laboratory, Cornell University
Interviewed by Mark Turin on 12 November 2008 (video)

Yervant Terzian, "Edwin E. Salpeter," Biographical Memoirs of the National Academy of Sciences (2009)
{{DEFAULTSORT:Salpeter, Edwin Ernest 1924 births 2008 deaths Members of the United States National Academy of Sciences Austrian emigrants to Australia Australian expatriates in England Australian emigrants to the United States 20th-century American astronomers Jewish scientists 20th-century Australian astronomers Foreign members of the Royal Society Members of the Eurasian Astronomical Society Cornell University faculty Recipients of the Gold Medal of the Royal Astronomical Society Fellows of the Australian Academy of Science Alumni of the University of Birmingham Members of the American Philosophical Society People educated at Sydney Boys High School