Erik Holmberg (13 November 1908 – 1 February 2000) was a Swedish astronomer and cosmologist. He is most famous for his work in the effects of
interacting galaxies
Interacting galaxies (''colliding galaxies'') are galaxies whose gravitational fields result in a disturbance of one another. An example of a minor interaction is a satellite galaxy disturbing the primary galaxy's spiral arms. An example of a ...
. This research showed that galaxies that came near each other would likely combine to form a larger galaxy.
Personal life
In 1908, Holmberg was born to Malcolm and Anna Holmberg in Skillingaryd, Sweden. In 1947 he married Martha Asdahl. They had one daughter named Osa, who was born in 1953. He died on 1 February 2000 in Gothenburg, at the age of 91.
Scientific work
In 1941, Holmberg performed arguably the first
N-body simulation
In physics and astronomy, an ''N''-body simulation is a simulation of a dynamical system of particles, usually under the influence of physical forces, such as gravity (see ''n''-body problem for other applications). ''N''-body simulations ar ...
on the dynamics of interacting galaxies. In order to simulate the effect, he constructed an array of 37 lightbulbs. Using photocells, he measured the simulated force of gravity. Over time, the galaxies moved closer toward each other. He also concluded in a later experiment that
elliptical galaxies
An elliptical galaxy is a type of galaxy with an approximately ellipsoidal shape and a smooth, nearly featureless image. They are one of the four main classes of galaxy described by Edwin Hubble in his Hubble sequence and 1936 work ''The Real ...
are generally older than
spiral galaxies
Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''Holmberg radius, a measure for the size of a galaxy on the sky, is named after him.
The ''Holmberg effect'' is also named after his observation that the satellite galaxies of a disk galaxy tend to be located along the disk galaxy minor axis. The evidences of such effect remain however debated.
See also
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Holmberg II
Holmberg II is a dwarf galaxy in the constellation Ursa Major. Its apparent magnitude is 11,1m and it is 11 million light years away from Earth. The galaxy is dominated by huge glowing gas bubbles, which are regions of star formation.
Holmberg ...
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Holmberg IX
Holmberg IX is a dwarf irregular galaxy and a satellite galaxy of M81, located in the constellation of Ursa Major. The galaxy is named after Erik Holmberg who first described it. Based on the observed age distribution of stars it contains it ...