Ernst Öpik

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Ernst Öpik
Kreis Wierland, governorate of Estonia Russian Empire (current Estonia)
Died10 September 1985(1985-09-10) (aged 91)
Bangor, Northern Ireland, United Kingdom
NationalityEstonian
Alma mater
Awards
Scientific career
FieldsAstronomy
InstitutionsArmagh Observatory

Ernst Julius Öpik (22 October [

astrophysicist who spent the second half of his career (1948–1981) at the Armagh Observatory in Northern Ireland. He is best known for his pioneering work on solar system dynamics.[1]

Education

Öpik was born in

meteors. He completed his 1923 doctorate at the University of Tartu
.

Astronomical work

He was the first and longest serving editor of the Irish Astronomical Journal (1950 to 1980) and frequently published his own research there.

ο2 Eridani B
, he determined its density as 25,000 times the density of the Sun but concluded that the result is impossible.[2]

In 1922 he published a paper in which he estimated the distance to the Andromeda Galaxy. He determined the distance using a novel astrophysical method based on the observed rotational velocities of the galaxy, which depends on the total mass around which stars are rotating, and on the assumption that the luminosity per unit mass was the same as that of our galaxy. He concluded that the distance was 450 kpc. His result was in good accordance with other estimates of these days (100 to 1000 kpc) and were closer to recent estimates (778 kpc) than Hubble's result (275 kpc).[3] His method is still widely used.

In 1922 he correctly predicted the frequency of

space probes
.

In 1932 he postulated a theory concerning the origins of comets in the

Edwin Salpeter's paper on the same subject had already been published by the time Öpik's paper reached Britain and the United States.[7]

Yarkovsky effect connection

The

Ivan Osipovich Yarkovsky
(1844–1902), who worked on scientific problems in his spare time. Writing in a pamphlet around the year 1900, Yarkovsky noted that the diurnal heating of a rotating object in space would cause it to experience a force that, while tiny, could lead to large long-term effects in the orbits of small bodies, especially meteoroids and small asteroids. Yarkovsky's work might have been forgotten had it not been for Öpik, who read Yarkovsky's pamphlet sometime around 1909. Decades later, Öpik discussed the possible importance of the Yarkovsky effect for moving meteoroids about the solar system.

Exile

Öpik fled his native country in 1944 because the approaching

University of Maryland
, which he visited annually, typically for one semester. As air travel became more common, his refusal to fly made travel to the U.S. from Armagh systematically more difficult and he eventually ceased the annual ritual.

Awards

He won the J. Lawrence Smith Medal from the National Academy of Sciences in 1960, the Meteoritical Society Frederick C. Leonard Memorial Medal in 1968, the Kepler Gold Medal from the American Association for the Advancement of Science & Meteoritical Society in 1972, the Gold Medal of the Royal Astronomical Society in 1975 and the Bruce Medal in 1976.

Papers

Books

Legacy

The Oort cloud is sometimes called "Öpik-Oort cloud". The Comet Interceptor's Optical Periscopic Imager for Comets (OPIC) instrument is named after Ernst Öpik to celebrate the first Estonia's contribution to a science mission of the European Space Agency.[9]

The

Öpik on the Martian moon Phobos
is also named for him.

He was the father of the atomic physicist Uuno Öpik. His grandson, Lembit Öpik, was the Liberal Democrat Member of Parliament for Montgomeryshire in Wales from 1997 to 2010.

References

  1. ^ a b "Fifty Years of the Irish Astronomical Journal" Fifty Years of the Irish Astronomical Journal, by A.G. Gunn & J. McFarland, Irish Astronomical Journal, vol. 27, iss. 1, p. 7 (2000)
  2. doi:10.1086/142296
    .
  3. doi:10.1086/142680
    .
  4. PMID 16588103
    .
  5. ^ "Rocking Camera – Armagh Observatory". Archived from the original on 26 February 2013. Retrieved 26 August 2012.
  6. ^ "Rocking-mirror Meteor Camera – Armagh Observatory". Archived from the original on 4 March 2016. Retrieved 26 August 2012.
  7. ^ Salpeter, Edwin E. "A Generalist Looks Back". Annual Review of Astronomy and Astrophysics. 2002. 40:1–25. pg. 9
  8. OCLC 837979
    .
  9. ^ "Estonian technology to be part of the European Space Agency's mission for the first time, University of Tartu, 26.06.2019".

External links

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