Asaph Hall III (October 15, 1829 – November 22, 1907) was an
AmericanThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
astronomerAstronomy is the scientific study of celestial objects and phenomena that originate outside the Earth's atmosphere...
who is most famous for having discovered the moons of
MarsMars is the fourth planet from the Sun in the Solar System. The planet is named after Mars, the Roman god of war. It is also referred to as the "Red Planet" because of its reddish appearance, due to iron oxide prevalent on its surface....
(namely
DeimosDeimos , is the smaller and outer of Mars’ two moons . It is named after Deimos, a figure representing dread in Greek Mythology. Its systematic designation is '.-Discovery:...
and
PhobosPhobos is the larger and closer of two small moons of Mars, the other being Deimos. It is named after the Greek god Phobos , a son of Ares...
) in 1877. He determined the orbits of
satelliteIn the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavor. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....
s of other planets and of
double starIn observational astronomy, a double star is a pair of stars that appear close to each other in the sky as seen from Earth when viewed through an optical telescope...
s, the rotation of
SaturnSaturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Saturn, along with Jupiter, Uranus and Neptune, is classified as a gas giant...
, and the mass of Mars.
Hall was born in
Goshen, ConnecticutGoshen is a town in Litchfield County, Connecticut, United States. The population was 2,697 at the 2000 census.Each July, the Connecticut Agricultural Fair is held in town.-Geography:...
, the son of Asaph Hall II, a clockmaker, and Hannah Palmer. His father died when he was 13, leaving the family in financial difficulty, so Asaph left school at 16 to become an apprentice to a carpenter.
Asaph Hall III (October 15, 1829 – November 22, 1907) was an
AmericanThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
astronomerAstronomy is the scientific study of celestial objects and phenomena that originate outside the Earth's atmosphere...
who is most famous for having discovered the moons of
MarsMars is the fourth planet from the Sun in the Solar System. The planet is named after Mars, the Roman god of war. It is also referred to as the "Red Planet" because of its reddish appearance, due to iron oxide prevalent on its surface....
(namely
DeimosDeimos , is the smaller and outer of Mars’ two moons . It is named after Deimos, a figure representing dread in Greek Mythology. Its systematic designation is '.-Discovery:...
and
PhobosPhobos is the larger and closer of two small moons of Mars, the other being Deimos. It is named after the Greek god Phobos , a son of Ares...
) in 1877. He determined the orbits of
satelliteIn the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavor. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....
s of other planets and of
double starIn observational astronomy, a double star is a pair of stars that appear close to each other in the sky as seen from Earth when viewed through an optical telescope...
s, the rotation of
SaturnSaturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Saturn, along with Jupiter, Uranus and Neptune, is classified as a gas giant...
, and the mass of Mars.
Hall was born in
Goshen, ConnecticutGoshen is a town in Litchfield County, Connecticut, United States. The population was 2,697 at the 2000 census.Each July, the Connecticut Agricultural Fair is held in town.-Geography:...
, the son of Asaph Hall II, a clockmaker, and Hannah Palmer. His father died when he was 13, leaving the family in financial difficulty, so Asaph left school at 16 to become an apprentice to a carpenter. He later enrolled at the
Central CollegeNew-York Central College, McGrawville was an institution of higher learning founded by anti-slavery Baptists in 1849 in McGraw, New York. The college was notable because it educated blacks as well as whites in the time of southern slavery and northern segregation, and educated women with men at a...
in
McGrawville, New YorkNew Hudson is a town in Allegany County, New York, United States. The population was 736 at the 2000 census.The Town of New Hudson is on the west border of the county, northeast of Olean, New York.- History :The town was first settled around 1820....
, where he studied mathematics. There he took classes from an instructor of geometry and German,
Angeline StickneyChloe Angeline Stickney Hall suffragist, abolitionist, and mathematician, was the wife of astronomer Asaph Hall...
. In 1856 they married.
In 1856, he took a job at the
Harvard College ObservatoryThe Harvard College Observatory is an institution managing a complex of buildings and multiple instruments used for astronomical research by the Harvard University Department of Astronomy. It is located in Cambridge, Massachusetts, USA, and was founded in 1839...
in
Cambridge, MassachusettsCambridge is a city in Middlesex County, Massachusetts, United States, in the Greater Boston area. It was named in honor of the University of Cambridge in England, a nexus of the Puritan theology embraced by the town's founders. Notably, Cambridge is home to two internationally prominent...
, and turned out to be an expert computer of orbits. Hall became assistant astronomer at the US Naval Observatory in Washington DC in 1862, and within a year of his arrival he was made professor.
In 1875 Hall was given responsibility for the USNO 26-inch (66-cm) telescope, the largest refractor in the world at the time. It was with this telescope that he discovered Phobos and Deimos in August 1877. He also noticed a white spot on Saturn which he used as a marker to ascertain the planet's rotational period. In 1884, he showed that the position of the elliptical orbit of Saturn's moon,
HyperionHyperion is a moon of Saturn discovered by William Cranch Bond, George Phillips Bond and William Lassell in 1848. It is distinguished by its irregular shape, its chaotic rotation, and its unexplained sponge-like appearance....
, was
retrogradingRetrograde motion is in the direction opposite to the movement of something else, and is the contrary of direct or prograde motion. The idea of retrograde or prograde motion is useful in three contexts: for describing the orbits of celestial bodies, for describing the rotations of celestial...
by about 20° per year. Hall also investigated stellar
parallaxParallax is an apparent displacement or difference of orientation of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines...
es and the positions of the stars in the
PleiadesIn astronomy, the Pleiades, or seven sisters, are an open star cluster containing relatively young hot blue stars located in the constellation of Taurus. It is among the nearest star clusters to Earth and is the cluster most obvious to the naked eye in the night sky...
clusterAn open cluster is a group of up to a few thousand stars that were formed from the same giant molecular cloud, and are still loosely gravitationally bound to each other. In contrast, globular clusters are very tightly bound by gravity. Open clusters have been found only in spiral and irregular...
.
Hall was responsible for apprenticing Henry S. Pritchett at the Naval Observatory in 1875.
On June 5, 1872 Hall submitted an article entitled "On an Experimental Determination of Pi" to the journal
Messenger of MathematicsThe Messenger of Mathematics is a defunct journal of mathematics.The chief editor was William Allen Whitworth with Charles Taylor, and volumes 1-58 were published between 1872 and 1929...
. The article appeared in the 1873 edition of the journal, volume 2, pages 113-114. In this article Hall reported the results of an experiment in random sampling that Hall had persuaded his friend, Captain O.C. Fox, to perform when Fox was recuperating from a wound received at the
Second Battle of Bull RunThe Second Battle of Bull Run, or, as it was called by the Confederacy, the Battle of Second Manassas, was fought August 28–30, 1862, as part of the American Civil War. It was the culmination of an offensive campaign waged by Confederate Gen. Robert E. Lee's Army of Northern Virginia against...
. The experiment involved repetitively throwing at random a fine steel wire onto a plane wooden surface ruled with equidistant parallel lines. Pi was computed as 2ml/an where m is the number of trials, l is the length of the steel wire, a is the distance between parallel lines, and n was the number of intersections. This paper is a very early documented use of random sampling (which
Nicholas MetropolisNicholas Constantine Metropolis was a Greek American physicist.-Work:Metropolis received his B.Sc. and Ph.D. degrees in physics at the University of Chicago...
would name the
Monte Carlo methodMonte Carlo methods are a class of computational algorithms that rely on repeated random sampling to compute their results. Monte Carlo methods are often used when simulating physical and mathematical systems. Because of their reliance on repeated computation of random or pseudo-random numbers,...
during the
Manhattan ProjectThe Manhattan Project was the codename for a project conducted during World War II to develop the first atomic bomb. The project was led by the United States, and included scientists from Denmark, The United Kingdom and Canada...
of
World War IIWorld War II, or the Second World War , was a global military conflict which involved a majority of the world's nations, including all great powers, organized into two opposing military alliances: the Allies and the Axis...
) in scientific inquiry.
Hall retired from the Navy in 1891. He became a lecturer in celestial mechanics at Harvard University in 1896, and continued to teach there until 1901.
Asaph and Angeline had four children. All graduated from Harvard University. His son
Asaph Hall JrAsaph Hall Jr was an American astronomer. He the son of Asaph Hall. He grew up in Washington, DC while his father worked at the United States Naval Observatory. Hall graduated from Harvard University in 1881, and received a doctoral degree from Yale in 1889...
also became an astronomer, Samuel Stickney Hall died at thirty after beginning a career in insurance, Angelo Hall became a
UnitarianUnitarian Universalism is a theologically liberal religion characterized by its support for a "free and responsible search for truth and meaning." Unitarian Universalists do not share a creed; rather, they are unified by their shared search for spiritual growth...
Minister and professor of mathematics at the US Naval Academy, and
Percival HallPercival Hall, was the second president of Gallaudet University . He was a strong advocate of the use of sign language in the education of the deaf, and also an advocate for deaf rights to vote, work, participate in sports, marry, and drive automobiles.The son of astronomer Asaph Hall, III and...
became the second president of
Gallaudet UniversityGallaudet University is a federally chartered, quasi-governmental university for the education of the deaf and hard-of-hearing, located in Washington, D.C...
. Angeline Hall died in 1892. Asaph Hall married Mary Gauthier after he fully retired to
Goshen, ConnecticutGoshen is a town in Litchfield County, Connecticut, United States. The population was 2,697 at the 2000 census.Each July, the Connecticut Agricultural Fair is held in town.-Geography:...
in 1901.
Asaph Hall died in November, 1907 while visiting his son, Angelo, in Annapolis, Maryland.
Awards and honors
He won the Lalande Prize of the
French Academy of SciencesThe French Academy of Sciences is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French scientific research...
in 1878, the
Gold Medal of the Royal Astronomical SocietyThe Gold Medal is the highest award 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...
in 1879, the Arago Medal in 1893, and was made a Chevalier in the Ordre national de la Légion d'honneur (French Legion of Honor).
Hall craterHall is a lunar crater named in honor of American astronomer Asaph Hall that is located in the southeast part of the Lacus Somniorum, a lunar mare in the northeast part of the Moon. This feature can be found to the west of the prominent walled plain Posidonius. Just to the south, and nearly...
on the
MoonThe Moon is Earth's only natural satellite and the fifth largest satellite in the Solar System. The average centre-to-centre distance from the Earth to the Moon is , about thirty times the diameter of the Earth. The common centre of mass of the system is located at about —a quarter the Earth's...
as well as Hall crater on the Martian moon Phobos are named in his honor.
Asteroidthumb|260px|right|[[253 Mathilde]], a [[C-type asteroid]] measuring about across. Photograph taken in 1997 by the [[NEAR Shoemaker]] probe.Asteroids, sometimes called minor planets or planetoids, are small Solar System bodies in orbit around the Sun, especially in the inner Solar System; they are...
3299 Hall3299 Hall is a Main-belt Asteroid discovered on October 10, 1980 by Shoemaker, C. at Palomar.- External links :*...
is also named in his honor.
External links