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. Major mergers occur between galaxies with similar amounts of mass, whereas minor mergers involve galaxies with masses ...
. This research showed that galaxies that came near each other would likely combine to form a larger galaxy.
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, ''n''-body problem for other applications). ''N''-body ...
on the dynamics of interacting galaxies.
In order to simulate the effect, he constructed an array of 37 lightbulbs.
Using photocells, he was able to measure the simulated force of gravity - because both gravity and light would follow an
inverse square law
In science, an inverse-square law is any scientific law stating that the observed "intensity" of a specified physical quantity is inversely proportional to the square of the distance from the source of that physical quantity. The fundamental cau ...
. He concluded that, over time, the 'galaxies' would move 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 three main classes of galaxy described by Edwin Hubble in his Hubble sequence and 1936 work ''The Re ...
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'' , among other discoveries.
The
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
*
Holmberg II
*
Holmberg IX
*
Holmberg 15A
References
20th-century Swedish astronomers
Swedish cosmologists
1908 births
2000 deaths
Members of the Royal Swedish Academy of Sciences
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