Donald C. Backer
Encyclopedia
Donald C. Backer was an American
astrophysicist who primarily worked in radio astronomy
. Backer made important contributions to the understanding and study of pulsar
s, including the discovery of the first millisecond pulsar
, black hole
s, and the epoch of reionization
.
, New Jersey
. He attended Cornell University
, where he earned a Bachelor's degree
in engineering physics
(B.E.P.) from Cornell University
in June 1966. He received a Master of Science
degree in radio astronomy
from Manchester University in 1968, and then returned to Cornell to earn his doctorate
in astronomy
in May 1971. Backer then took post-doctoral positions first at NRAO in Charlottesville
, Virginia
(1971–1973), and then at NASA
/GSFC in Greenbelt
, Maryland
(1973-1975). In 1975, Backer moved to the University of California, Berkeley
as a research astronomer in the Radio Astronomy Laboratory, and became professor
of astronomy at Berkeley in 1989. Backer served as the acting chair of the Berkeley Astronomy Department from 1998-1999, 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.
s. He discovered the first millisecond pulsar, PSR B1937+21
, which rotates at a rate far beyond what was expected of pulsars before its discovery. Backer was also involved in the discovery of a Jupiter
-sized planet around PSR B1620-26
, thought to be the oldest known extrasolar planet. Backer pioneered efforts to detect gravitational wave
s from rapidly rotating neutron star
s, aiming to set limits on the gravitational wave background of the universe
.
Backer was also a pioneer in Very Long Baseline Interferometry
, a technique in radio astronomy used to achieve high angular resolution images of astronomical sources. His efforts here were directed towards understanding Sagittarius A*, the supermassive black hole
at the center of the Milky Way
.
Backer then moved on to studying reionization
, leading a collaboration between the University of California, Berkeley
, the University of Virginia
, the University of Pennsylvania
, and NRAO called the Precision Array to Probe the Epoch of Reionization (PAPER). The project consists of two arrays of antenna, one in West Virginia
and the other in South Africa
. 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
was neutral, and by doing so study the first objects that formed in the universe.
fraternity at Cornell University and through that organization the Irving Literary
Society. He also served on countless national and international committees in astronomy, including the American Astronomical Society
(AAS); the International Scientific Radio Union (URSI); and the International Astronomical Union
(IAU).
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
astrophysicist who primarily worked in radio astronomy
Radio astronomy
Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The initial detection of radio waves from an astronomical object was made in the 1930s, when Karl Jansky observed radiation coming from the Milky Way. Subsequent observations have identified a number of...
. Backer made important contributions to the understanding and study of pulsar
Pulsar
A pulsar is a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. The radiation can only be observed when the beam of emission is pointing towards the Earth. This is called the lighthouse effect and gives rise to the pulsed nature that gives pulsars their name...
s, including the discovery of the first millisecond pulsar
Millisecond pulsar
A millisecond pulsar is a pulsar with a rotational period in the range of about 1-10 milliseconds. Millisecond pulsars have been detected in the radio, X-ray, and gamma ray portions of the electromagnetic spectrum. The origin of millisecond pulsars is still unknown...
, 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, and the epoch of reionization
Reionization
In Big Bang cosmology, reionization is the process that reionized the matter in the universe after the "dark ages," and is the second of two major phase changes of gas in the universe. As the majority of baryonic matter is in the form of hydrogen, reionization usually refers to the reionization of...
.
Biography
Backer was born in PlainfieldPlainfield, New Jersey
Plainfield is a city in Union County, New Jersey, United States. As of the 2010 United States Census, the city's population increased to a record high of 49,808....
, New Jersey
New Jersey
New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...
. He attended 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 earned a Bachelor's degree
Bachelor's degree
A bachelor's degree is usually an academic degree awarded for an undergraduate course or major that generally lasts for three or four years, but can range anywhere from two to six years depending on the region of the world...
in engineering physics
Engineering physics
Engineering physics is the study of the combined disciplines of physics, engineering and mathematics in order to develop an understanding of the interrelationships of these three disciplines. Fundamental physics is combined with problem solving and engineering skills, which then has broad...
(B.E.P.) from 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...
in June 1966. He received a Master of Science
Master of Science
A Master of Science is a postgraduate academic master's degree awarded by universities in many countries. The degree is typically studied for in the sciences including the social sciences.-Brazil, Argentina and Uruguay:...
degree in radio astronomy
Radio astronomy
Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The initial detection of radio waves from an astronomical object was made in the 1930s, when Karl Jansky observed radiation coming from the Milky Way. Subsequent observations have identified a number of...
from Manchester University in 1968, and then returned to Cornell to earn his doctorate
Doctorate
A doctorate is an academic degree or professional degree that in most countries refers to a class of degrees which qualify the holder to teach in a specific field, A doctorate is an academic degree or professional degree that in most countries refers to a class of degrees which qualify the holder...
in astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
in May 1971. Backer then took post-doctoral positions first at NRAO in Charlottesville
Charlottesville, Virginia
Charlottesville is an independent city geographically surrounded by but separate from Albemarle County in the Commonwealth of Virginia, United States, and named after Charlotte of Mecklenburg-Strelitz, the queen consort of King George III of the United Kingdom.The official population estimate for...
, Virginia
Virginia
The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...
(1971–1973), and then at NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
/GSFC in Greenbelt
Greenbelt, Maryland
Greenbelt is a city in Prince George's County, Maryland, United States. Contained within today's City of Greenbelt is the historic planned community now known locally as "Old Greenbelt" and designated as the Greenbelt Historic District...
, Maryland
Maryland
Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...
(1973-1975). In 1975, Backer moved to the University of California, Berkeley
University of California, Berkeley
The University of California, Berkeley , is a teaching and research university established in 1868 and located in Berkeley, California, USA...
as a research astronomer in the Radio Astronomy Laboratory, and became professor
Professor
A professor is a scholarly teacher; the precise meaning of the term varies by country. Literally, professor derives from Latin as a "person who professes" being usually an expert in arts or sciences; a teacher of high rank...
of astronomy at Berkeley in 1989. Backer served as the acting chair of the Berkeley Astronomy Department from 1998-1999, 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.
Research
Backer's early work focused on pulsarPulsar
A pulsar is a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. The radiation can only be observed when the beam of emission is pointing towards the Earth. This is called the lighthouse effect and gives rise to the pulsed nature that gives pulsars their name...
s. He discovered the first millisecond pulsar, PSR B1937+21
PSR B1937+21
PSR B1937+21 is a pulsar located in the constellation Vulpecula a few degrees in the sky away from the first discovered pulsar, PSR B1919+21. The name PSR B1937+21 is derived from the word "pulsar" and the declination and right ascension at which it is located, with the "B" indicating that the...
, which rotates at a rate far beyond what was expected of pulsars before its discovery. Backer was also involved in the discovery of a Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
-sized planet around PSR B1620-26
PSR B1620-26
PSR B1620-26 is a binary star system located at a distance of 3,800 parsecs in the globular cluster of Messier 4 in the constellation of Scorpius. The system is composed of a pulsar and a white dwarf...
, thought to be the oldest known extrasolar planet. Backer pioneered efforts to detect gravitational wave
Gravitational wave
In physics, gravitational waves are theoretical ripples in the curvature of spacetime which propagates as a wave, traveling outward from the source. Predicted to exist by Albert Einstein in 1916 on the basis of his theory of general relativity, gravitational waves theoretically transport energy as...
s from rapidly rotating neutron star
Neutron star
A neutron star is a type of stellar remnant that can result from the gravitational collapse of a massive star during a Type II, Type Ib or Type Ic supernova event. Such stars are composed almost entirely of neutrons, which are subatomic particles without electrical charge and with a slightly larger...
s, aiming to set limits on the gravitational wave background of the universe
Universe
The Universe is commonly defined as the totality of everything that exists, including all matter and energy, the planets, stars, galaxies, and the contents of intergalactic space. Definitions and usage vary and similar terms include the cosmos, the world and nature...
.
Backer was also a pioneer in Very Long Baseline Interferometry
Very Long Baseline Interferometry
Very Long Baseline Interferometry is a type of astronomical interferometry used in radio astronomy. It allows observations of an object that are made simultaneously by many telescopes to be combined, emulating a telescope with a size equal to the maximum separation between the telescopes.Data...
, a technique in radio astronomy used to achieve high angular resolution images of astronomical sources. His efforts here were directed towards understanding Sagittarius A*, the supermassive black hole
Supermassive black hole
A supermassive black hole is the largest type of black hole in a galaxy, in the order of hundreds of thousands to billions of solar masses. Most, and possibly all galaxies, including the Milky Way, are believed to contain supermassive black holes at their centers.Supermassive black holes have...
at the center of the Milky Way
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...
.
Backer then moved on to studying reionization
Reionization
In Big Bang cosmology, reionization is the process that reionized the matter in the universe after the "dark ages," and is the second of two major phase changes of gas in the universe. As the majority of baryonic matter is in the form of hydrogen, reionization usually refers to the reionization of...
, leading a collaboration between the University of California, Berkeley
University of California, Berkeley
The University of California, Berkeley , is a teaching and research university established in 1868 and located in Berkeley, California, USA...
, the University of Virginia
University of Virginia
The University of Virginia is a public research university located in Charlottesville, Virginia, United States, founded by Thomas Jefferson...
, the University of Pennsylvania
University of Pennsylvania
The University of Pennsylvania is a private, Ivy League university located in Philadelphia, Pennsylvania, United States. Penn is the fourth-oldest institution of higher education in the United States,Penn is the fourth-oldest using the founding dates claimed by each institution...
, and NRAO called the Precision Array to Probe the Epoch of Reionization (PAPER). The project consists of two arrays of antenna, one in West Virginia
West Virginia
West Virginia is a state in the Appalachian and Southeastern regions of the United States, bordered by Virginia to the southeast, Kentucky to the southwest, Ohio to the northwest, Pennsylvania to the northeast and Maryland to the east...
and the other in South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
. These arrays are simple long wavelength telescopes that hope to detect the redshifted hydrogen line
Hydrogen line
The hydrogen line, 21 centimeter line or HI line refers to the electromagnetic radiation spectral line that is created by a change in the energy state of neutral hydrogen atoms. This electromagnetic radiation is at the precise frequency of 1420.40575177 MHz, which is equivalent to the vacuum...
from a time very early in the history of the universe when hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
was neutral, and by doing so study the first objects that formed in the universe.
Member
Don Backer joined the Phi Kappa PsiPhi Kappa Psi
Phi Kappa Psi is an American collegiate social fraternity founded at Jefferson College in Canonsburg, Pennsylvania on February 19, 1852. There are over a hundred chapters and colonies at accredited four year colleges and universities throughout the United States. More than 112,000 men have been...
fraternity at Cornell University and through that organization the Irving Literary
The Irving Literary Society (Cornell University)
Cornell literary societies were a group of 19th century student organizations at Cornell University, in Ithaca, New York, formed for the purpose of promoting language skills and oratory. The U.S...
Society. He also served on countless national and international committees in astronomy, including the American Astronomical Society
American Astronomical Society
The American Astronomical Society is an American society of professional astronomers and other interested individuals, headquartered in Washington, DC...
(AAS); the International Scientific Radio Union (URSI); and the International Astronomical Union
International Astronomical Union
The International Astronomical Union IAU is a collection of professional astronomers, at the Ph.D. level and beyond, active in professional research and education in astronomy...
(IAU).