Jaan Einasto (born 23 February 1929) is an

Estonia Estonia, officially the Republic of Estonia, is a country in Northern Europe. It is bordered to the north by the Gulf of Finland across from Finland, to the west by the Baltic Sea across from Sweden, to the south by Latvia, and to the east by Ru ...

n astrophysicist and one of the discoverers of the large-scale structure of the

Universe The universe is all of space and time and their contents. It comprises all of existence, any fundamental interaction, physical process and physical constant, and therefore all forms of matter and energy, and the structures they form, from s ...

Family and early life

Born Jaan Eisenschmidt in

Tartu Tartu is the second largest city in Estonia after Tallinn. Tartu has a population of 97,759 (as of 2024). It is southeast of Tallinn and 245 kilometres (152 miles) northeast of Riga, Latvia. Tartu lies on the Emajõgi river, which connects the ...

, the name "Einasto" is an anagram of "Estonia" (it was chosen by his patriotic father in the 1930s to replace the family's German name). Einasto married and had 3 children, 2 daughters and the youngest, a son. His daughter, Maret, is also an astrophysicist, who collaborates with her father.

Education and career

He attended the

University of Tartu The University of Tartu (UT; ; ) is a public research university located in the city of Tartu, Estonia. It is the national university of Estonia. It is also the largest and oldest university in the country.

, where he received the Ph.D. equivalent in 1955 and a senior research doctorate in 1972. From 1952, he has worked as a scientist at the Tartu

Observatory An observatory is a location used for observing terrestrial, marine, or celestial events. Astronomy, climatology/meteorology, geophysics, oceanography and volcanology are examples of disciplines for which observatories have been constructed. Th ...

(1977–1998) Head of the Department of

Cosmology Cosmology () is a branch of physics and metaphysics dealing with the nature of the universe, the cosmos. The term ''cosmology'' was first used in English in 1656 in Thomas Blount's ''Glossographia'', with the meaning of "a speaking of the wo ...

; from 1992–1995, he was Professor of Cosmology at the University of Tartu. For a long time, he was Head of the Division of

Astronomy Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest includ ...

and

Physics Physics is the scientific study of matter, its Elementary particle, fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge whi ...

of the

Estonian Academy of Sciences Founded in 1938, the Estonian Academy of Sciences (, ) is Estonia's national academy of science in Tallinn. As with other national academies, it is an independent group of well-known scientists whose stated aim is to promote research and develo ...

Tallinn Tallinn is the capital city, capital and List of cities in Estonia, most populous city of Estonia. Situated on a Tallinn Bay, bay in north Estonia, on the shore of the Gulf of Finland of the Baltic Sea, it has a population of (as of 2025) and ...

. Einasto is a member of the

Academia Europaea The Academia Europaea is a pan-European Academy of humanities, letters, law, and sciences. The Academia was founded in 1988 as a functioning Europe-wide Academy that encompasses all fields of scholarly inquiry. It acts as co-ordinator of Europe ...

, the

European Astronomical Society The European Astronomical Society (EAS) is a learned society, founded under the Swiss Civil Code in 1990, as an association to contribute and promote the advancement of astronomy in Europe, and to deal with astronomical matters at a European lev ...

and the

Royal Astronomical Society The Royal Astronomical Society (RAS) is a learned society and charitable organisation, charity that encourages and promotes the study of astronomy, planetary science, solar-system science, geophysics and closely related branches of science. Its ...

; he has received three Estonian National Science Awards. *1947 Tartu Secondary School No. 1 *1952 University of Tartu *1955 Cand.Sc. in physics and mathematics *1972 D.Sc. in physics and mathematics *1992 Professor Since 1991 he is member of Academia Europaea. Since 1994 he is member of the Royal Astronomical Society. In 1974, in a seminal work with Kaasik and Saar at the

Tartu Observatory The Tartu Observatory () is the largest astronomy, astronomical observatory in Estonia. On 1 January 2018, Tartu Observatory was joined again to the University of Tartu, and the observatory is now an institute of the university. It is located o ...

, Einasto argued that "it is necessary to adopt an alternative hypothesis: that the clusters of galaxies are stabilised by hidden matter." This was a key paper in recognizing that a hidden matter, i.e.,

dark matter In astronomy, dark matter is an invisible and hypothetical form of matter that does not interact with light or other electromagnetic radiation. Dark matter is implied by gravity, gravitational effects that cannot be explained by general relat ...

, could explain observational anomalies in astronomy. Einasto showed in 1977 at a Symposium in Tallinn (Estonia) that the universe has a cell structure, in which the observed matter surrounds huge empty voids.

Awards, honours, legacy

The

asteroid An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...

11577 Einasto, discovered in 1994, is named in his honour. The Einasto Supercluster, a galaxy supercluster discovered in 2024, is named in his honour.

References

External links

Jaan Einasto
page at the Tõravere Observatory 1929 births Cosmologists Living people Estonian astrophysicists Estonian astronomers 20th-century Estonian physicists Members of Academia Europaea Members of the Estonian Academy of Sciences Recipients of the Order of the National Coat of Arms, 2nd Class University of Tartu alumni Hugo Treffner Gymnasium alumni Scientists from Tartu {{Europe-astronomer-stub

Family and early life

Education and career

Awards, honours, legacy

See also

References

External links