Bengt Georg Daniel Strömgren (January 21, 1908 – July 4, 1987) was a Danish astronomer and astrophysicist. January 21 is the 21st day of the year in the Gregorian Calendar. ... 1908 is a leap year starting on Wednesday (link will take you to calendar). ... July 4 is the 185th day of the year (186th in leap years) in the Gregorian Calendar, with 180 days remaining. ... 1987 is a common year starting on Thursday of the Gregorian calendar. ... The Kingdom of Denmark is geographically the smallest Nordic country and is part of the European Union. ... Astronomy, which etymologically means law of the stars, (from Greek: αστρονομία = άστρον + νόμος) is a science involving the observation and explanation of events occurring outside Earth and its atmosphere. ... Spiral Galaxy ESO 269-57 Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties ( luminosity, density, temperature and chemical composition) of astronomical objects such as stars, galaxies, and the interstellar medium, as well as their interactions. ...

Bengt Strömgren was born in Gothenburg. His parents were Hedvig Strömgren (née Lidforss) and Svante Elis Strömgren, who was professor of astronomy at the University of Copenhagen and director of the University Observatory in Copenhagen. Bengt grew up in the professor's mansion surrounded with scientists, assistants, observers and guests. His father paced and promoted Bengt into a life with science, and Bengt's first paper was published already at the age of 14. He graduated from high school in 1925 and enrolled at the Copenhagen university. Only two years later, he graduated in astronomy and atomic physics, and during the following two years, he completed a doctoral degree, which was evaluated with the best marks in December 1929, when he was 21 years old. Gothenburg (Swedish: Göteborg [jøːtəbɔrj]) is a city and a municipality on the western coast of Sweden, in the County of Västra Götaland. ... Astronomy, which etymologically means law of the stars, (from Greek: αστρονομία = άστρον + νόμος) is a science involving the observation and explanation of events occurring outside Earth and its atmosphere. ... University of Copenhagen The University of Copenhagen (Danish: Københavns Universitet) is the oldest and largest university and research institution in Copenhagen, Denmark. ... Events January-May January 3 - Benito Mussolini announces he is taking dictatorial powers over Italy. ... Atomic physics (or atom physics) is physics of the electron hull of atoms. ... A doctorate is an academic degree of the highest level. ... 1929 was a common year starting on Tuesday (link will take you to calendar). ...

He gained lots of useful experience from his studies in theoretical physics at Niels Bohr's Institute close by, and he was at the right place at the right time. He soon found out that he intended to use the fresh quantum physics in space, i.e. investigate the applications of quantum mechanics in stars. Obviously, questions of nepotism were in play when he applied for an assistantship already in 1925, which he didn't get. But only one year later it was given to him anyway — he was the best, regardless of his employer being also his own father. Theoretical physics attempts to understand the world by making a model of reality, used for rationalizing, explaining, predicting physical phenomena through a physical theory. There are three types of theories in physics; mainstream theories, proposed theories and fringe theories. ... Niels Bohr Niels Henrik David Bohr (October 7, 1885 – November 18, 1962) was a Danish physicist who made essential contributions to understanding atomic structure and quantum mechanics. ... Fig. ... Fig. ... Nepotism is the act of favoring ones family members in a situation where doing so is considered inappropriate. ... Events January-May January 3 - Benito Mussolini announces he is taking dictatorial powers over Italy. ...

After being appointed as lecturer at the university in 1932, Strömgren was invited to the University of Chicago in 1936 by Otto Struve. Going abroad for 18 months meant a lot to the young researcher, and when he went back to Denmark and to the rising national socialism in Europe, he succeded his father's professorship in 1940. During five years of isolation, under the German occupation of Denmark, he initiated the building of a new Danish Observatory, the Brorfelde Observatory. But after the Second World War, Bengt Strömgren became tired of lacking state funding for the project, and with a stagnant national economy, he felt that he had to leave Danish research, which he did in 1951. 1932 is a leap year starting on a Friday. ... The University of Chicago is a private co-educational university located in Chicago, Illinois. ... 1936 was a leap year starting on Wednesday (link will take you to calendar). ... The Kingdom of Denmark is geographically the smallest Nordic country and is part of the European Union. ... The Nazi party used a right-facing swastika as their symbol and the red and black colors were said to represent Blut und Boden (blood and soil). ... World map showing location of Europe A satellite composite image of Europe Europe is geologically and geographically a peninsula, forming the westernmost part of Eurasia. ... 1940 was a leap year starting on Monday (link will take you to calendar). ... The Federal Republic of Germany (German: Bundesrepublik Deutschland) is one of the worlds leading industrialised countries, located in the heart of Europe. ... Mushroom cloud from the nuclear explosion over Nagasaki rising 18 km into the air. ... 1951 was a common year starting on Monday; see its calendar. ...

He went to the United States and became director of the Yerkes and McDonald Observatories, and stayed there for six years. In 1957, he was appointed the first professor of theoretical astrophysics at Princeton, where he got Albert Einstein's office. In 1959 he was awarded the Bruce Medal and in 1962 he won the Gold Medal of the Royal Astronomical Society. In 1965 he won the Henry Norris Russell Lectureship. He stayed at Princeton with his family until 1967, when he went back to his homeland Denmark, and became the last resident in a series of great Danish scientists of the Carlsberg Mansion og Honoer, which had earlier been occupied by Niels Bohr among others. In 1987, he passed away after a short period of illness. The United States of America — also referred to as the United States, the U.S.A., the U.S., America, the States, or (archaically) Columbia—is a federal republic of 50 states located primarily in central North America (with the exception of two states: Alaska and Hawaii). ... The 102-cm (40 inch) refractor at the Yerkes Observatory. ... Aerial view of the McDonald Observatory. ... 1957 was a common year starting on Tuesday (link will take you to calendar). ... Princeton University, located in Princeton, New Jersey, is one of the eight Ivy League universities, and is widely recognized as one of the most prestigious institutions in the world. ... Portrait of Albert Einstein taken by Yousuf Karsh on February 11, 1948 Albert Einstein (March 14, 1879 – April 18, 1955) was a theoretical physicist who is widely regarded as the greatest scientist of the 20th century. ... 1959 was a common year starting on Thursday (link will take you to calendar). ... The Catherine Wolfe Bruce gold medal is awarded every year by the Astronomical Society of the Pacific for outstanding lifetime contributions to astronomy. ... 1962 was a common year starting on Monday (link will take you to calendar). ... The Gold Medal is the highest award of the Royal Astronomical Society. ... 1965 was a common year starting on Friday (the link is to a full 1965 calendar). ... The Henry Norris Russell Lectureship is awarded each year by the American Astronomical Society in recognition of a lifetime of excellence in astronomical research. ... Niels Bohr Niels Henrik David Bohr (October 7, 1885 – November 18, 1962) was a Danish physicist who made essential contributions to understanding atomic structure and quantum mechanics. ...

Bengt Strömgren made momentous contributions to astrophysics. He found that the chemical composition of stars was very much different than previously assumed. In the late 1930s, he found the relative abundance of hydrogen to be nearly 70 %, and helium to be about 27 %. Just before the war, he discovered the so-called Strömgren Spheres — huge interstellar shells of ionized hydrogen around stars. And in the 1950s and 1960s, he pioneered photoelectric photometry with a novel four-color system, now called Strömgren photometry. A chemical substance is any material substance used in or obtained by a process in chemistry: A chemical compound is a substance consisting of two or more chemical elements that are chemically combined in fixed proportions. ... For alternate meanings see star (disambiguation) Hundreds of stars are visible in this image taken by the Hubble Space Telescope of the Sagittarius Star Cloud in the Milky Way Galaxy. ... Events and trends Technology Jet engine invented Science Nuclear fission discovered by Otto Hahn, Lise Meitner and Fritz Strassmann Pluto, the ninth planet from the Sun, is discovered by Clyde Tombaugh British biologist Arthur Tansley coins term ecosystem War, peace and politics Socialists proclaim The death of Capitalism Rise to... General Name, Symbol, Number Hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1 (IA), 1 , s Density, Hardness 0. ... General Name, Symbol, Number Helium, He, 2 Atomic weight 4. ... Events and trends Technology United States tests the first fusion bomb. ... Centuries: 19th century - 20th century - 21st century Decades: 1900s 1910s 1920s 1930s 1940s 1950s - 1960s - 1970s 1980s 1990s 2000s 2010s Years: 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 Events and trends The 1960s was a turbulent decade of change around the world. ...

The asteroid 1846 Bengt was named after him.

External links

• Bruce Medalist Bengt Strömgren (http://phys-astro.sonoma.edu/BruceMedalists/Stromgren/)
• Biographical PhD Project on Bengt Strömgren and Modern Astrophysics (http://www.ivh.au.dk/personale/simon_olling_rebsdorf/home.html)