Orest Khvolson
Encyclopedia
Orest Danilovich Khvolson or Chwolson (November 22 (N.S. December 4), 1852, Saint Petersburg
- May 11, 1934, Leningrad
) was a Russia
n physicist
and honorary member of the Soviet Academy of Sciences (1920). He is most noted for being one of the first to study the gravitational lens
effect.
Orest, son of the noted Orientalist Daniel Chwolson, graduated from St.Petersburg University in 1873. He began teaching at his alma mater
in 1876 and would become a professor in 1891. Orest Khvolson authored a number of works on electricity
, magnetism
, photometry
, and actinometry. He proposed the designs of actinometer
and pyrheliometer
, which would be used by the Russian weather station
s for a long time. After 1896, Khvolson was mainly engaged in compiling the five-volume Physics Course (Курс физики), which would improve immensely the teaching of physics
throughout the country and remain a principal textbook in universities for years to come. It was even translated into the German
, French
, and Spanish
languages.
His most noted accomplishment was in 1924, when he published about gravitational lenses in Astronomische Nachrichten
, a scientific journal on astronomy. The concept of gravitational lenses, did not get much attention until 1936, when Albert Einstein wrote about the gravitational lens effect. The observation of a gravitational lens, where one source (sun or galaxy) produces a ring around another source is referred to as an Chwolson ring, or Einstein ring
.
He became an honorary member of the Soviet Academy of Sciences, awarded the Order of the Red Banner of Labor. The crater Khvolson
on the Moon
is named after him.
Saint Petersburg
Saint Petersburg is a city and a federal subject of Russia located on the Neva River at the head of the Gulf of Finland on the Baltic Sea...
- May 11, 1934, Leningrad
Saint Petersburg
Saint Petersburg is a city and a federal subject of Russia located on the Neva River at the head of the Gulf of Finland on the Baltic Sea...
) was a Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
n physicist
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...
and honorary member of the Soviet Academy of Sciences (1920). He is most noted for being one of the first to study the gravitational lens
Gravitational lens
A gravitational lens refers to a distribution of matter between a distant source and an observer, that is capable of bending the light from the source, as it travels towards the observer...
effect.
Orest, son of the noted Orientalist Daniel Chwolson, graduated from St.Petersburg University in 1873. He began teaching at his alma mater
Alma mater
Alma mater , pronounced ), was used in ancient Rome as a title for various mother goddesses, especially Ceres or Cybele, and in Christianity for the Virgin Mary.-General term:...
in 1876 and would become a professor in 1891. Orest Khvolson authored a number of works on electricity
Electricity
Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...
, magnetism
Magnetism
Magnetism is a property of materials that respond at an atomic or subatomic level to an applied magnetic field. Ferromagnetism is the strongest and most familiar type of magnetism. It is responsible for the behavior of permanent magnets, which produce their own persistent magnetic fields, as well...
, photometry
Photometry (optics)
Photometry is the science of the measurement of light, in terms of its perceived brightness to the human eye. It is distinct from radiometry, which is the science of measurement of radiant energy in terms of absolute power; rather, in photometry, the radiant power at each wavelength is weighted by...
, and actinometry. He proposed the designs of actinometer
Actinometer
Actinometers are instruments used to measure the heating power of radiation. They are used in meteorology to measure solar radiation as pyrheliometers.An actinometer is a chemical system or physical device which determines the number of...
and pyrheliometer
Pyrheliometer
A pyrheliometer is an instrument for direct measurement of solar irradiance. Sunlight enters the instrument through awindow and is directed onto a thermopile which converts heat to an electrical signal that can be recorded. The signal voltage is converted via a formula to measure watts per square...
, which would be used by the Russian weather station
Weather station
A weather station is a facility, either on land or sea, with instruments and equipment for observing atmospheric conditions to provide information for weather forecasts and to study the weather and climate. The measurements taken include temperature, barometric pressure, humidity, wind speed, wind...
s for a long time. After 1896, Khvolson was mainly engaged in compiling the five-volume Physics Course (Курс физики), which would improve immensely the teaching of physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
throughout the country and remain a principal textbook in universities for years to come. It was even translated into the German
German language
German is a West Germanic language, related to and classified alongside English and Dutch. With an estimated 90 – 98 million native speakers, German is one of the world's major languages and is the most widely-spoken first language in the European Union....
, French
French language
French is a Romance language spoken as a first language in France, the Romandy region in Switzerland, Wallonia and Brussels in Belgium, Monaco, the regions of Quebec and Acadia in Canada, and by various communities elsewhere. Second-language speakers of French are distributed throughout many parts...
, and Spanish
Spanish language
Spanish , also known as Castilian , is a Romance language in the Ibero-Romance group that evolved from several languages and dialects in central-northern Iberia around the 9th century and gradually spread with the expansion of the Kingdom of Castile into central and southern Iberia during the...
languages.
His most noted accomplishment was in 1924, when he published about gravitational lenses in Astronomische Nachrichten
Astronomische Nachrichten
Astronomische Nachrichten , one of the first international journals in the field of astronomy, was founded in 1821 by the German astronomer Heinrich Christian Schumacher. It claims to be the oldest astronomical journal in the world that is still being published...
, a scientific journal on astronomy. The concept of gravitational lenses, did not get much attention until 1936, when Albert Einstein wrote about the gravitational lens effect. The observation of a gravitational lens, where one source (sun or galaxy) produces a ring around another source is referred to as an Chwolson ring, or Einstein ring
Einstein ring
In observational astronomy an Einstein ring is the deformation of the light from a source into a ring through gravitational lensing of the source's light by an object with an extremely large mass . This occurs when the source, lens and observer are all aligned...
.
He became an honorary member of the Soviet Academy of Sciences, awarded the Order of the Red Banner of Labor. The crater Khvolson
Khvol'son (crater)
Khvol'son is a crater on the far side of the Moon. It lies just to the east-southeast of the large walled plain Pasteur. Less than a crater diameter to the north-northeast of Khvol'son is the crater Meitner, and just to the east-southeast lies Kondratyuk....
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...
is named after him.
Important publications
- Traité de physique O.-D. Chwolson (French translation of Kurs fiziki by E. Davaux) Paris : A. Hermann, 1906–1928