Carl Wilhelm Wirtz
Encyclopedia
Carl Wilhelm Wirtz was an astronomer
who spent his time between Germany
and the Observatory of Strasbourg
.
As already Vesto Slipher
in 1912, Wirtz in 1918 observed a systematic redshift
of nebula
e, which was difficult to interpret in terms of a cosmological model
in which the Universe
is filled more or less uniformly with star
s and nebulae
. Wirtz additionally used the equivalent in German of K correction
. The term continues to be used in present-day observational cosmology, but Wirtz's observational evidence that the Universe
is expanding is not often mentioned. He wrote:
In 1922, he wrote a paper where he argued that the observational results suggest, that the redshifts of distant galaxies are becoming higher than more closer ones, which he interpreted as an increase of their radial velocities with distance, and that larger masses have smaller redshifts than smaller ones.
In another note of the same year, he argued that counter-clockwise spiraling galaxies have smaller redshifts than clockwise spiraling ones.
In 1924 he obtained more precise results, and interpreted them both as a confirmation of an increase of radial velocities with distance, but also as confirmation of a de Sitter universe
, in which the increase of redshift is seen as caused by an increased time dilation
in distant parts of the universe.
In 1936, Wirtz wrote a short paper alluding to the priority for his 1922-conclusion that the radial velocities of galaxies are increasing with their distance.
Astronomer
An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...
who spent his time between Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
and the Observatory of Strasbourg
Observatory of Strasbourg
The Observatory of Strasbourg is an astronomical observatory in Strasbourg, France.Following the Franco-Prussian War of 1870–71, the city of Strasbourg became part of the German Empire. The University of Strasbourg was refounded in 1872 and a new observatory began construction in 1875...
.
As already Vesto Slipher
Vesto Slipher
Vesto Melvin Slipher was an American astronomer. His brother Earl C. Slipher was also an astronomer and a director at the Lowell Observatory....
in 1912, Wirtz in 1918 observed a systematic redshift
Redshift
In physics , redshift happens when light seen coming from an object is proportionally increased in wavelength, or shifted to the red end of the spectrum...
of nebula
Nebula
A nebula is an interstellar cloud of dust, hydrogen gas, helium gas and other ionized gases...
e, which was difficult to interpret in terms of a cosmological model
Physical cosmology
Physical cosmology, as a branch of astronomy, is the study of the largest-scale structures and dynamics of the universe and is concerned with fundamental questions about its formation and evolution. For most of human history, it was a branch of metaphysics and religion...
in which the Universe
Universe
The Universe is commonly defined as the totality of everything that exists, including all matter and energy, the planets, stars, galaxies, and the contents of intergalactic space. Definitions and usage vary and similar terms include the cosmos, the world and nature...
is filled more or less uniformly with star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
s and nebulae
Nebula
A nebula is an interstellar cloud of dust, hydrogen gas, helium gas and other ionized gases...
. Wirtz additionally used the equivalent in German of K correction
K correction
K correction is a correction to an astronomical object's magnitude that allows a measurement of a quantity of light from an object at a redshift z to be converted to an equivalent measurement in the rest frame of the object. If one could measure all the light from an object at all wavelengths , a...
. The term continues to be used in present-day observational cosmology, but Wirtz's observational evidence that the Universe
Universe
The Universe is commonly defined as the totality of everything that exists, including all matter and energy, the planets, stars, galaxies, and the contents of intergalactic space. Definitions and usage vary and similar terms include the cosmos, the world and nature...
is expanding is not often mentioned. He wrote:
In 1922, he wrote a paper where he argued that the observational results suggest, that the redshifts of distant galaxies are becoming higher than more closer ones, which he interpreted as an increase of their radial velocities with distance, and that larger masses have smaller redshifts than smaller ones.
In another note of the same year, he argued that counter-clockwise spiraling galaxies have smaller redshifts than clockwise spiraling ones.
In 1924 he obtained more precise results, and interpreted them both as a confirmation of an increase of radial velocities with distance, but also as confirmation of a de Sitter universe
De Sitter universe
A de Sitter universe is a cosmological solution to Einstein's field equations of General Relativity which is named after Willem de Sitter. It models the universe as spatially flat and neglects ordinary matter, so the dynamics of the universe are dominated by the cosmological constant, thought to...
, in which the increase of redshift is seen as caused by an increased time dilation
Time dilation
In the theory of relativity, time dilation is an observed difference of elapsed time between two events as measured by observers either moving relative to each other or differently situated from gravitational masses. An accurate clock at rest with respect to one observer may be measured to tick at...
in distant parts of the universe.
In 1936, Wirtz wrote a short paper alluding to the priority for his 1922-conclusion that the radial velocities of galaxies are increasing with their distance.
External links
- Carl Wilhelm Wirtz @ Astrophysics Data SystemAstrophysics Data SystemThe Astrophysics Data System , developed by the National Aeronautics and Space Administration , is an online database of over eight million astronomy and physics papers from both peer reviewed and non-peer reviewed sources...