Bertil Lindblad (26 November 1895 – 25 June 1965) was a Swedish

astronomer An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galax ...

. After finishing his secondary education at Örebro högre allmänna läroverk, Lindblad matriculated at

Uppsala University Uppsala University (UU) () is a public university, public research university in Uppsala, Sweden. Founded in 1477, it is the List of universities in Sweden, oldest university in Sweden and the Nordic countries still in operation. Initially fou ...

in 1914. He received his ''filosofie magister'' degree in 1917, his ''filosofie licentiat'' degree in 1918 and completed his doctorate and became a docent at the university in 1920. From 1927 he was professor and astronomer of the

Royal Swedish Academy of Sciences The Royal Swedish Academy of Sciences () is one of the Swedish Royal Academies, royal academies of Sweden. Founded on 2 June 1739, it is an independent, non-governmental scientific organization that takes special responsibility for promoting nat ...

and head of the

Stockholm Observatory The Stockholm Observatory (, IAU code#050, 050) is an astronomical observatory and institution in Stockholm, Sweden, founded in the 18th century and today part of Stockholm University. In 1931, the new Stockholm Observatory (, IAU code#052, 052), ...

. In the latter capacity he was responsible for the observatory's move from the old building in the centre of Stockholm to a newly built facility in Saltsjöbaden Observatory, which was opened in 1931. Lindblad studied the theory of the rotation of

galaxies A galaxy is a system of stars, stellar remnants, interstellar gas, dust, and dark matter bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar Sys ...

. By making careful observations of the apparent motions of stars, he was able to study the rotation of the

Milky Way The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galax ...

. He deduced that the rate of rotation of the stars in the outer part of the galaxy, where the Sun is located, decreased with distance from the galactic core. This deduction was soon confirmed by

Jan Oort Jan Hendrik Oort ( or ; 28 April 1900 – 5 November 1992) was a Dutch astronomer who made significant contributions to the understanding of the Milky Way and who was a pioneer in the field of radio astronomy. ''The New York Times'' called him ...

in 1927. A certain class of

resonances Resonance is a phenomenon that occurs when an object or system is subjected to an external force or vibration whose frequency matches a resonant frequency (or resonance frequency) of the system, defined as a frequency that generates a maximu ...

in rotating stellar or

gaseous Gas is a state of matter that has neither a fixed volume nor a fixed shape and is a compressible fluid. A ''pure gas'' is made up of individual atoms (e.g. a noble gas like neon) or molecules of either a single type of atom ( elements such as ...

disks are named Lindblad resonances, after Bertil Lindblad. His son, Per Olof Lindblad, also became an astronomer.

Honors

Awards * Janssen Medal from the

French Academy of Sciences The French Academy of Sciences (, ) is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French Scientific method, scientific research. It was at the forefron ...

(1938) *

Prix Jules Janssen The Prix Jules Janssen is the highest award of the Société astronomique de France (SAF), the French astronomical society. This annual prize is given to a professional French astronomer or to an astronomer of another nationality in recognition ...

, the highest award of the

Société astronomique de France The Société astronomique de France (SAF; ), the France, French astronomical society, is a non-profit association in the public interest organized under French law (Association loi de 1901). Founded by astronomer Camille Flammarion in 1887, its ...

, the French astronomical society (1949) *

Gold Medal of the Royal Astronomical Society The Gold Medal of the Royal Astronomical Society is the highest award given by the Royal Astronomical Society (RAS). The RAS Council have "complete freedom as to the grounds on which it is awarded" and it can be awarded for any reason. Past awar ...

(1948) *

Bruce Medal The 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 ...

(1954) Named after him * Lindblad (crater) on the

Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

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 ...

1448 Lindbladia

References

{{DEFAULTSORT:Lindblad, Bertil 1895 births 1965 deaths 20th-century Swedish astronomers Uppsala University alumni Recipients of the Gold Medal of the Royal Astronomical Society Foreign associates of the National Academy of Sciences Presidents of the International Astronomical Union People from Örebro