Seth Barnes Nicholson
Encyclopedia
Seth Barnes Nicholson was an American
astronomer
.
Nicholson was born in Springfield, Illinois
and was raised in rural Illinois
. He was educated at Drake University
where he became interested in astronomy.
In 1914, at the University of California
's Lick Observatory
, while observing the recently-discovered Jupiter
moon
Pasiphaë
, he discovered a new one: Sinope
, whose orbit
he computed for his Ph.D.
thesis in 1915.
He spent his entire career at Mount Wilson Observatory
, where he discovered three more Jovian moons: Lysithea
and Carme
in 1938 and Ananke
in 1951, as well as a Trojan asteroid
1647 Menelaus
, and computed orbits of several comet
s and of Pluto
.
Sinope, Lysithea, Carme and Ananke were simply designated as "Jupiter IX", "Jupiter X", "Jupiter XI" and "Jupiter XII". They were not given their present names until 1975. Nicholson himself declined to propose names.
At Mt. Wilson, his main assignment concerned solar activity and he produced for decades annual reports on sunspot
activity. He also made a number of eclipse
expeditions to measure the brightness and temperature of the Sun's corona
.
In the early 1920s, he and Edison Pettit
made the first systematic infrared
observations of celestial objects.
They used a vacuum thermocouple
to measure the infrared radiation and thus the temperature of the Moon
which led to the theory that the Moon was covered with a thin layer of dust acting as an insulator, and also of the planets, sunspots and stars.
Their temperatures measurements of nearby giant star
s led to some of the first determinations of stellar diameters.
From 1943 to 1955, he served as editor of the Publications of the Astronomical Society of the Pacific
, of which he was also twice president.
He died in Los Angeles
.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
astronomer
Astronomer
An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...
.
| Asteroid Asteroid Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones... s discovered: 2 |
|
|---|---|
| 878 Mildred 878 Mildred 878 Mildred is a minor planet in the main belt orbiting the Sun. It is the lowest numbered, and thus the namesake, of the Mildred family of asteroids, a subgroup of the Nysa family... |
September 6, 1916 |
| 1647 Menelaus 1647 Menelaus 1647 Menelaus is a Jupiter Trojan asteroid that orbits in the Lagrangian point of the Sun-Jupiter system, in the "Greek Camp" of Trojan asteroids. It was named after the Greek hero Menelaus. It was discovered by Seth Barnes Nicholson on June 23, 1957 in Palomar, California at the Palomar... |
June 23, 1957 |
Nicholson was born in Springfield, Illinois
Springfield, Illinois
Springfield is the third and current capital of the US state of Illinois and the county seat of Sangamon County with a population of 117,400 , making it the sixth most populated city in the state and the second most populated Illinois city outside of the Chicago Metropolitan Area...
and was raised in rural Illinois
Illinois
Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...
. He was educated at Drake University
Drake University
Drake University is a private, co-educational university located in Des Moines, Iowa, USA. The institution offers a number of undergraduate and graduate programs, as well as professional programs in law and pharmacy. Today, Drake is one of the twenty-five oldest law schools in the country....
where he became interested in astronomy.
In 1914, at the University of California
University of California
The University of California is a public university system in the U.S. state of California. Under the California Master Plan for Higher Education, the University of California is a part of the state's three-tier public higher education system, which also includes the California State University...
's Lick Observatory
Lick Observatory
The Lick Observatory is an astronomical observatory, owned and operated by the University of California. It is situated on the summit of Mount Hamilton, in the Diablo Range just east of San Jose, California, USA...
, while observing the recently-discovered 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,...
moon
Natural satellite
A natural satellite or moon is a celestial body that orbits a planet or smaller body, which is called its primary. The two terms are used synonymously for non-artificial satellites of planets, of dwarf planets, and of minor planets....
Pasiphaë
Pasiphaë (moon)
Pasiphaë is a retrograde irregular satellite of Jupiter. It was discovered in 1908 by Philibert Jacques Melotte and later named after the mythological Pasiphaë, wife of Minos and mother of the Minotaur from Greek legend....
, he discovered a new one: Sinope
Sinope (moon)
Sinope is a retrograde irregular satellite of Jupiter discovered by Seth Barnes Nicholson at Lick Observatory in 1914, and is named after Sinope of Greek mythology....
, whose orbit
Orbit
In physics, an orbit is the gravitationally curved path of an object around a point in space, for example the orbit of a planet around the center of a star system, such as the Solar System...
he computed for his 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...
thesis in 1915.
He spent his entire career at Mount Wilson Observatory
Mount Wilson Observatory
The Mount Wilson Observatory is an astronomical observatory in Los Angeles County, California, United States. The MWO is located on Mount Wilson, a 5,715 foot peak in the San Gabriel Mountains near Pasadena, northeast of Los Angeles...
, where he discovered three more Jovian moons: Lysithea
Lysithea (moon)
Lysithea is a prograde irregular satellite of Jupiter. It was discovered by Seth Barnes Nicholson in 1938 at Mount Wilson Observatory and is named after the mythological Lysithea, daughter of Oceanus and one of Zeus' lovers....
and Carme
Carme (moon)
Carme is a retrograde irregular satellite of Jupiter. It was discovered by Seth Barnes Nicholson at Mount Wilson Observatory in California in July 1938. It is named after the mythological Carme, mother by Zeus of Britomartis, a Cretan goddess....
in 1938 and Ananke
Ananke (moon)
Ananke is a retrograde irregular satellite of Jupiter. It was discovered by Seth Barnes Nicholson at Mount Wilson Observatory in 1951 and is named after the mythological Ananke, the personification of Necessity, and the mother of the Moirae by Zeus...
in 1951, as well as a Trojan asteroid
Trojan asteroid
The Jupiter Trojans, commonly called Trojans or Trojan asteroids, are a large group of objects that share the orbit of the planet Jupiter around the Sun. Relative to Jupiter, each Trojan librates around one of the planet's two Lagrangian points of stability, and , that respectively lie 60° ahead...
1647 Menelaus
1647 Menelaus
1647 Menelaus is a Jupiter Trojan asteroid that orbits in the Lagrangian point of the Sun-Jupiter system, in the "Greek Camp" of Trojan asteroids. It was named after the Greek hero Menelaus. It was discovered by Seth Barnes Nicholson on June 23, 1957 in Palomar, California at the Palomar...
, and computed orbits of several comet
Comet
A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...
s and of Pluto
Pluto
Pluto, formal designation 134340 Pluto, is the second-most-massive known dwarf planet in the Solar System and the tenth-most-massive body observed directly orbiting the Sun...
.
Sinope, Lysithea, Carme and Ananke were simply designated as "Jupiter IX", "Jupiter X", "Jupiter XI" and "Jupiter XII". They were not given their present names until 1975. Nicholson himself declined to propose names.
At Mt. Wilson, his main assignment concerned solar activity and he produced for decades annual reports on sunspot
Sunspot
Sunspots are temporary phenomena on the photosphere of the Sun that appear visibly as dark spots compared to surrounding regions. They are caused by intense magnetic activity, which inhibits convection by an effect comparable to the eddy current brake, forming areas of reduced surface temperature....
activity. He also made a number of eclipse
Eclipse
An eclipse is an astronomical event that occurs when an astronomical object is temporarily obscured, either by passing into the shadow of another body or by having another body pass between it and the viewer...
expeditions to measure the brightness and temperature of the Sun's corona
Corona
A corona is a type of plasma "atmosphere" of the Sun or other celestial body, extending millions of kilometers into space, most easily seen during a total solar eclipse, but also observable in a coronagraph...
.
In the early 1920s, he and Edison Pettit
Edison Pettit
Edison Pettit was an American astronomer.He was born in Peru, Nebraska. He taught astronomy at Washburn College in Topeka, Kansas from 1914 to 1918. He married Hannah Steele, who was an assistant at Yerkes Observatory, and received his Ph.D...
made the first systematic infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
observations of celestial objects.
They used a vacuum thermocouple
Thermocouple
A thermocouple is a device consisting of two different conductors that produce a voltage proportional to a temperature difference between either end of the pair of conductors. Thermocouples are a widely used type of temperature sensor for measurement and control and can also be used to convert a...
to measure the infrared radiation and thus the temperature of 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...
which led to the theory that the Moon was covered with a thin layer of dust acting as an insulator, and also of the planets, sunspots and stars.
Their temperatures measurements of nearby giant star
Red giant
A red giant is a luminous giant star of low or intermediate mass in a late phase of stellar evolution. The outer atmosphere is inflated and tenuous, making the radius immense and the surface temperature low, somewhere from 5,000 K and lower...
s led to some of the first determinations of stellar diameters.
From 1943 to 1955, he served as editor of the Publications of the Astronomical Society of the Pacific
Astronomical Society of the Pacific
The Astronomical Society of the Pacific is a scientific and educational organization, founded in San Francisco on February 7, 1889. Its name derives from its origins on the Pacific Coast, but today it has members all over the country and the world...
, of which he was also twice president.
He died in Los Angeles
Los Angeles, California
Los Angeles , with a population at the 2010 United States Census of 3,792,621, is the most populous city in California, USA and the second most populous in the United States, after New York City. It has an area of , and is located in Southern California...
.
Awards and honors
- Awarded the Bruce MedalBruce MedalThe Catherine Wolfe Bruce Gold Medal is awarded every year by the Astronomical Society of the Pacific for outstanding lifetime contributions to astronomy. It is named after Catherine Wolfe Bruce, an American patroness of astronomy, and was first awarded in 1898...
(1963) - The AsteroidAsteroidAsteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
1831 Nicholson1831 Nicholson1831 Nicholson is a main belt asteroid discovered on April 17, 1968 by P. Wild at Zimmerwald. It is named after the astronomer Seth B. Nicholson.- External links :*...
, the crater NicholsonNicholson (lunar crater)Nicholson is a lunar impact crater located at the western limb. In this position it is subject to libration, which can limit observation. The crater is also viewed at a very oblique angle, so it is seen from the side when observed from the Earth. It is an irregular, somewhat pear-shaped formation...
on the MoonMoonThe 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 crater NicholsonNicholson (Martian crater)Nicholson is a crater on Mars centered at 0.1° N and 164.5° W. It is 62 miles wide , and located in the Memnonia quadrangle. Nicholson is a good marker for the equator as it sits almost directly on the martian equator...
on MarsMarsMars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...
, and Nicholson Regio on GanymedeGanymede (moon)Ganymede is a satellite of Jupiter and the largest moon in the Solar System. It is the seventh moon and third Galilean satellite outward from Jupiter. Completing an orbit in roughly seven days, Ganymede participates in a 1:2:4 orbital resonance with the moons Europa and Io, respectively...
were named after him.