Forest Ray Moulton
Encyclopedia
Forest Ray Moulton was an American astronomer
.
He was born in Le Roy, Michigan
, and was educated at Albion College
. After graduating in 1894 (A.B.
), he performed his graduate studies at the University of Chicago
and gained a Ph.D.
in 1899. At the University of Chicago he was associate in astronomy (1898–1900), instructor (1900–03), assistant professor (1903–08), associate professor (1908–12), and professor
after 1912.
He is noted for being a proponent, along with Thomas Chamberlin, of the Chamberlin-Moulton planetesimal hypothesis
that the planets coalesced from smaller bodies they termed planetesimal
s. Their hypothesis called for the close passage of another star to trigger this condensation, a concept that has since fallen out of favor.
In the first decades of the twentieth century, some additional small satellites were discovered to be in orbit around Jupiter
. Dr. Moulton proposed that these were actually gravitationally-captured planetesimals. This theory has become well-accepted among astronomers.
The crater Moulton
on the Moon
, the Adams-Moulton methods for solving differential equations and the Moulton plane
in geometry are named after him.
in 1907 and a research associate of the Carnegie Institution in 1908. Besides various contributions to mathematical and astronomical journals he was the author of:
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
.
He was born in Le Roy, Michigan
Le Roy, Michigan
Le Roy is a village in Osceola County of the U.S. state of Michigan. As of the 2000 census, the village population was 267. The village is located within Le Roy Township.-Geography:...
, and was educated at Albion College
Albion College
Albion College is a private liberal arts college located in Albion, Michigan. Related to the United Methodist Church, it was founded in 1835 and was the first private college in Michigan to have a chapter of Phi Beta Kappa. It has a student population of about 1500.The school's sports teams are...
. After graduating in 1894 (A.B.
Bachelor of Arts
A Bachelor of Arts , from the Latin artium baccalaureus, is a bachelor's degree awarded for an undergraduate course or program in either the liberal arts, the sciences, or both...
), he performed his graduate studies at the University of Chicago
University of Chicago
The University of Chicago is a private research university in Chicago, Illinois, USA. It was founded by the American Baptist Education Society with a donation from oil magnate and philanthropist John D. Rockefeller and incorporated in 1890...
and gained a Ph.D.
Doctor of Philosophy
Doctor of Philosophy, abbreviated as Ph.D., PhD, D.Phil., or DPhil , in English-speaking countries, is a postgraduate academic degree awarded by universities...
in 1899. At the University of Chicago he was associate in astronomy (1898–1900), instructor (1900–03), assistant professor (1903–08), associate professor (1908–12), and 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...
after 1912.
He is noted for being a proponent, along with Thomas Chamberlin, of the Chamberlin-Moulton planetesimal hypothesis
Chamberlin-Moulton planetesimal hypothesis
The Chamberlin–Moulton planetesimal hypothesis was proposed in 1905 by geologist Thomas Chrowder Chamberlin and astronomer Forest Ray Moulton to describe the formation of the solar system...
that the planets coalesced from smaller bodies they termed planetesimal
Planetesimal
Planetesimals are solid objects thought to exist in protoplanetary disks and in debris disks.A widely accepted theory of planet formation, the so-called planetesimal hypothesis of Viktor Safronov, states that planets form out of cosmic dust grains that collide and stick to form larger and larger...
s. Their hypothesis called for the close passage of another star to trigger this condensation, a concept that has since fallen out of favor.
In the first decades of the twentieth century, some additional small satellites were discovered to be in orbit around 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,...
. Dr. Moulton proposed that these were actually gravitationally-captured planetesimals. This theory has become well-accepted among astronomers.
The crater Moulton
Moulton (crater)
Moulton is a crater on the Moon's far side, just beyond the south-southwestern limb as seen from the Earth. The crater is attached to the southern edge of Chamberlin, and it lies at the northern terminus of the Vallis Schrödinger valley. There is a cleft in the shared rim between Chamberlin and...
on the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
, the Adams-Moulton methods for solving differential equations and the Moulton plane
Moulton plane
In incidence geometry, the Moulton plane is an example of an affine plane in which Desargues' theorem does not hold. It is named after the American astronomer Forest Ray Moulton...
in geometry are named after him.
Writings
He became an associate editor of the Transactions of the American Mathematical SocietyTransactions of the American Mathematical Society
Transactions of the American Mathematical Society is a monthly mathematics journal published by the American Mathematical Society. It started in 1900...
in 1907 and a research associate of the Carnegie Institution in 1908. Besides various contributions to mathematical and astronomical journals he was the author of:
- An Introduction to Celestial Mechanics (1902; second revised edition, 1914)
- An Introduction to Astronomy (1905)
- Descriptive Astronomy (1912)
- Periodic OrbitsOrbit (dynamics)In mathematics, in the study of dynamical systems, an orbit is a collection of points related by the evolution function of the dynamical system. The orbit is a subset of the phase space and the set of all orbits is a partition of the phase space, that is different orbits do not intersect in the...
(1913) - Differential Equations (1930)