Karl Schwarzschild

Karl Schwarzschild (October 9th 1873, Francfort-sur-le-Main - May 11th 1916, Potsdam) was a German astrophysicist.

Its curiosity for the stars appeared as of its first school years, when it built a small telescope. Witness of this interest, his father presented it to a friend mathematician who had a private observatory. Schwarszchild learned how to use a telescope and studied mathematics more advanced than at the school. It became famous as of the 16 years age for its theory of the Orbite S.

He studied at the university of Strasbourg, then from Munich, and obtained his Doctorat at the 23 years age for work on the theories of Henri Poincaré. He was then engaged as an assistant at the Kuffner Observatory in Ottakring. He devoted himself mainly to the photometry: he achieves a work of pioneer to improve the photographic plates and to establish their use in Astronomie, as in the spectral study of the star S. He developed in particular a formula modelling the evolution of the sensitivity of a photosensitive material according to the duration and of illumination:

i = F (I \ cdot t^p),

where p is exhibitor of Schwarschild , and is worth between 0,6 and 0,7, which represents the fact that the more exposed one film is, the less it is sensitive.

Of 1901 with 1909, it officiated as professor at the prestigious institute of Göttingen, where it on the occasion to work with personalities such as David Hilbert and Hermann Minkowski. It occupied then a station at the Observatory of Astrophysics of Potsdam in 1909.

It in addition stated the laws of transport and radiative balance, the ellipsoidal movement of stars and discovered the Pression of radiation. One also owes him of work on the atomic structure and the associated radiations of which it identified quantum nature .

It is the first to have found a solution with the gravitational equations of Einstein in 1916. With the Metric of Schwarzschild, it showed that in the equations describing the Gravitation of a quantity of Matière concentrated in a point, it appears a Singularité, which is in fact only apparent, as shows it the Métrique of Kruskal-Szekeres.

It is also the first to have defined the laws of interaction between the magnetic fields and the Lumière, and to have described the phenomena of curve of the luminous rays in the vicinity of gravitational points, thus contributing to found the theory of the Black hole (cf Rayon of Schwarzschild).

Engaged on the Russian face by the German army as an artillerist, it lute for the first time the formulation of the General relativity of Einstein in the edition of November 25th, 1915 of the Reports of the Academy of Prussia . At once, it started to seek the consequences which these laws could have on the Gravitation of stars. As it would be very complicated mathematically to analyze a star in rotation or a not-spherical star, Schwarzschild was limited to the spherical stars which do not turn. It was initially interested to describe the outside of star mathematically, relegating to later their internal study. A few days later, it had calculated, in all its details, starting from the equations of Einstein, the curve of the Espace-temps outside any spherical star which does not turn. Calculation was elegant, and the Géométrie curve which he predicted, the geometry of Schwarzschild, was to have an immense impact on our comprehension of the Universe.

It thus sent a letter to Einstein describing its calculations to him, that Einstein presented on its behalf to the Academy of Science of Prussia on January 13rd, 1916. A few weeks later, Einstein presented a second article of Schwarzschild: the exact calculation of the curve inside a star.

Hardly four months later, on June 19th, Einstein had the sad task to announce the death of Schwarzschild to the Academy of Science of Prussia, following a disease contracted on the Russian face.

Observatory Karl Schwarzschild

The town of Iéna creates in 1960 an observatory in homage to its name.

The Asteroid (837) Schwarzschilda and a lunar crater was named in its honor.

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