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Donald Charles Backer (November 9, 1943 – July 25, 2010) was an American astrophysicist who primarily worked in
radio astronomy Radio astronomy is a subfield of astronomy that studies Astronomical object, celestial objects using radio waves. It started in 1933, when Karl Jansky at Bell Telephone Laboratories reported radiation coming from the Milky Way. Subsequent observat ...
. Backer made important contributions to the understanding and study of
pulsar A pulsar (''pulsating star, on the model of quasar'') is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its Poles of astronomical bodies#Magnetic poles, magnetic poles. This radiation can be obse ...
s (including the discovery of the first
millisecond pulsar A millisecond pulsar (MSP) is a pulsar with a rotational period less than about 10 milliseconds. Millisecond pulsars have been detected in radio pulsar, radio, X-ray pulsar, X-ray, and gamma ray portions of the electromagnetic spectrum. The leadi ...
),
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, and the epoch of reionization.


Biography

Backer was born in
Plainfield, New Jersey Plainfield is a City (New Jersey), city in Union County, New Jersey, Union County, in the U.S. state of New Jersey. Nicknamed "The Queen City",
. He attended
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 earned a
Bachelor's degree A bachelor's degree (from Medieval Latin ''baccalaureus'') or baccalaureate (from Modern Latin ''baccalaureatus'') is an undergraduate degree awarded by colleges and universities upon completion of a course of study lasting three to six years ...
in
engineering physics Engineering physics (EP), sometimes engineering science, is the field of study combining pure science disciplines (such as physics, mathematics, chemistry or biology) and engineering disciplines (computer, nuclear, electrical, aerospace, medic ...
(B.E.P.) from
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 ...
in 1966. He received a
Master of Science A Master of Science (; abbreviated MS, M.S., MSc, M.Sc., SM, S.M., ScM or Sc.M.) is a master's degree. In contrast to the Master of Arts degree, the Master of Science degree is typically granted for studies in sciences, engineering and medici ...
degree in
radio astronomy Radio astronomy is a subfield of astronomy that studies Astronomical object, celestial objects using radio waves. It started in 1933, when Karl Jansky at Bell Telephone Laboratories reported radiation coming from the Milky Way. Subsequent observat ...
from
Manchester University The University of Manchester is a public university, public research university in Manchester, England. The main campus is south of Manchester city centre, Manchester City Centre on Wilmslow Road, Oxford Road. The University of Manchester is c ...
in 1968, and then returned to Cornell to earn his
doctorate A doctorate (from Latin ''doctor'', meaning "teacher") or doctoral degree is a postgraduate academic degree awarded by universities and some other educational institutions, derived from the ancient formalism '' licentia docendi'' ("licence to teach ...
in
astronomy Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest includ ...
in 1971. Backer then took post-doctoral positions first at NRAO in
Charlottesville Charlottesville, colloquially known as C'ville, is an independent city in Virginia, United States. It is the seat of government of Albemarle County, which surrounds the city, though the two are separate legal entities. It is named after Quee ...
,
Virginia Virginia, officially the Commonwealth of Virginia, is a U.S. state, state in the Southeastern United States, Southeastern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States between the East Coast of the United States ...
(1971–1973), and then at
NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...
/ GSFC in Greenbelt,
Maryland Maryland ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic region of the United States. It borders the states of Virginia to its south, West Virginia to its west, Pennsylvania to its north, and Delaware to its east ...
(1973–1975). In 1975, Backer moved to the
University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California), is a Public university, public Land-grant university, land-grant research university in Berkeley, California, United States. Founded in 1868 and named after t ...
as a research astronomer in the Radio Astronomy Laboratory, and became
professor Professor (commonly abbreviated as Prof.) is an Academy, academic rank at university, universities and other tertiary education, post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin ...
of astronomy at Berkeley in 1989. Backer served as the acting chair of the Berkeley Astronomy Department from 1998 to 1999, as vice chair 1999–2001, and as chair 2002–2006 and 2007–2008. In 2008, he was appointed director of Berkeley's Radio Astronomy Laboratory. Backer collapsed outside his home and died on July 25, 2010. Donald C. Backer was married to the artist Lutz Bacher for almost 40 years.


Research

Backer's early work focused on
pulsar A pulsar (''pulsating star, on the model of quasar'') is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its Poles of astronomical bodies#Magnetic poles, magnetic poles. This radiation can be obse ...
s. He discovered the first
millisecond pulsar A millisecond pulsar (MSP) is a pulsar with a rotational period less than about 10 milliseconds. Millisecond pulsars have been detected in radio pulsar, radio, X-ray pulsar, X-ray, and gamma ray portions of the electromagnetic spectrum. The leadi ...
,
PSR B1937+21 PSR may refer to: Organizations * Pacific School of Religion, Berkeley, California, US * Palestinian Center for Policy and Survey Research * Payment Systems Regulator in the United Kingdom * Physicians for Social Responsibility, US Political par ...
, which rotates at 642 Hz (1.558 ms), a rate far beyond what was expected of pulsars before its discovery. Backer was also involved in the discovery of a
Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a Jupiter mass, mass more than 2.5 times that of all the other planets in the Solar System combined a ...
-sized planet around PSR B1620-26, thought to be the oldest known extrasolar planet. Backer pioneered efforts to detect
gravitational wave Gravitational waves are oscillations of the gravitational field that Wave propagation, travel through space at the speed of light; they are generated by the relative motion of gravity, gravitating masses. They were proposed by Oliver Heaviside i ...
s from rapidly rotating
neutron star A neutron star is the gravitationally collapsed Stellar core, core of a massive supergiant star. It results from the supernova explosion of a stellar evolution#Massive star, massive star—combined with gravitational collapse—that compresses ...
s, aiming to set limits on the gravitational wave background of the
universe The universe is all of space and time and their contents. It comprises all of existence, any fundamental interaction, physical process and physical constant, and therefore all forms of matter and energy, and the structures they form, from s ...
. Backer was also a pioneer in
Very Long Baseline Interferometry Very-long-baseline interferometry (VLBI) is a type of astronomical interferometry used in radio astronomy. In VLBI a signal from an astronomical radio source, such as a quasar, is collected at multiple radio telescopes on Earth or in space. T ...
, a technique in radio astronomy used to achieve high angular resolution images of astronomical sources. His efforts here were directed towards understanding
Sagittarius A* Sagittarius A*, abbreviated as Sgr A* ( ), is the supermassive black hole at the Galactic Center of the Milky Way. Viewed from Earth, it is located near the border of the constellations Sagittarius and Scorpius, about 5.6° south o ...
, the
supermassive black hole A supermassive black hole (SMBH or sometimes SBH) is the largest type of black hole, with its mass being on the order of hundreds of thousands, or millions to billions, of times the mass of the Sun (). Black holes are a class of astronomical ...
at the center of the
Milky Way The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galax ...
. Backer then moved on to studying
reionization In the fields of Big Bang theory and physical cosmology, cosmology, reionization is the process that caused electrically neutral atoms in the primordial universe to reionize after the lapse of the "Timeline of the Big Bang#Dark Ages, dark ages". ...
, leading a collaboration between the
University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California), is a Public university, public Land-grant university, land-grant research university in Berkeley, California, United States. Founded in 1868 and named after t ...
, the
University of Virginia The University of Virginia (UVA) is a Public university#United States, public research university in Charlottesville, Virginia, United States. It was founded in 1819 by Thomas Jefferson and contains his The Lawn, Academical Village, a World H ...
, the
University of Pennsylvania The University of Pennsylvania (Penn or UPenn) is a Private university, private Ivy League research university in Philadelphia, Pennsylvania, United States. One of nine colonial colleges, it was chartered in 1755 through the efforts of f ...
, and NRAO called the Precision Array for Probing the Epoch of Reionization (PAPER). The project consists of two arrays of antenna, one in
West Virginia West Virginia is a mountainous U.S. state, state in the Southern United States, Southern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States.The United States Census Bureau, Census Bureau and the Association of American ...
and the other in
South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...
. These arrays are simple long wavelength telescopes that hope to detect the redshifted hydrogen line from a time very early in the history of the universe when
hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...
was neutral, and by doing so study the first objects that formed in the universe.


Honors

* Karl G. Jansky Lectureship of the National Radio Astronomy Observatory in 2003


References

{{DEFAULTSORT:Backer, Donald C 1943 births 2010 deaths American astronomers Cornell University College of Engineering alumni People from Plainfield, New Jersey University of California, Berkeley College of Letters and Science faculty Alumni of the University of Manchester