Everything about Asaph Hall totally explained
Asaph Hall (
October 15,
1829 –
November 22,
1907) was an
American astronomer who is most famous for having discovered the moons of
Mars (namely
Deimos and
Phobos) in
1877. He determined the orbits of
satellites of other planets and of
double stars, the rotation of
Saturn, and the mass of Mars.
Hall was born in
Goshen, Connecticut. Apprenticed to a carpenter at 16, he later enrolled at the
Central College in
McGrawville, New York. In
1856 he married
Angeline Stickney. He and Angeline had 4 sons:
Asaph, Jr.,
Samuel,
Angelo, and
Percival
In
1856, he took a job at the
Harvard College Observatory in
Cambridge, Massachusetts, 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 66-cm/26-in telescope, the largest
refractor in the world at the time. It was with this telescope that he discovered Phobos and Deimos. 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,
Hyperion, was
retrograding by about 20° per year.
Hall also investigated stellar
parallaxes and the positions of the stars in the
Pleiades cluster.
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 Mathematics. 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 convinced his friend, Captain O.C. Fox, to perform when Fox was recuperating from a wound received at the
Second Battle of Bull Run. The experiment was 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 Metropolis would name the
Monte Carlo method during the
Manhattan Project of
World War II) in scientific inquiry.
Awards and honors
He won the
Gold Medal of the Royal Astronomical Society in
1879.
Hall crater on the
Moon as well as
Hall crater on the Martian moon Phobos are named in his honor.
Further Information
Get more info on 'Asaph Hall'.
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