| Jaan Einasto | |
| Birth Name: | Jaan Eisenschmidt |
| Birth Date: | 23 February 1929 |
| Birth Place: | Tartu, Estonia |
| Field: | Cosmology |
| Alma Mater: | University of Tartu (Ph.D., 1955) |
| Known For: | Pioneer in the branch of astronomy known as near-field cosmology[1] |
| Prizes: | Estonia National Science Award (1982, 1998, 2003, 2007) Marcel Grossmann Award (2009) Ambartsumian International Prize (2012) Gruber Prize in Cosmology[2] (2014) |
Jaan Einasto (born 23 February 1929) is an Estonian astrophysicist and one of the discoverers of the large-scale structure of the Universe.[3]
Born Jaan Eisenschmidt in Tartu, 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).[4]
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.[5]
He attended the University of Tartu, 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 (1977–1998) Head of the Department of Cosmology; 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 and Physics of the Estonian Academy of Sciences in Tallinn. Einasto is a member of the Academia Europaea, the European Astronomical Society and the Royal Astronomical Society; he has received three Estonian National Science Awards.
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, Einasto argued that "it is necessary to adopt an alternative hypothesis: that the clusters of galaxies are stabilised by hidden matter."[6] This was a key paper in recognizing that a hidden matter, i.e., dark matter, could explain observational anomalies in astronomy.[7] [8]
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.[9]
The asteroid 11577 Einasto, discovered in 1994, is named in his honour.
The Einasto Supercluster, a galaxy supercluster discovered in 2024, is named in his honour.[10]