The Redshift of Extragalactic Nebulae & On the Masses of Nebulae and of Clusters of Nebulae

March 16, 2023
2:00pm to 3:00pm

Red Room

Specialist level
David Alonso González

Red Room


David Alonso González will present the paper 'The Redshift of Extragalactic Nebulae' (Helvetica Physica Acta, Vol. 6, p. 110-127, 1933):

This gives a description of the most essential characteristics of extragalactic nebulae, as well as of the methods used to investigate these. In particular, the so-called redshift of extragalactic nebulae is discussed in detail. Various theories which have been proposed to explain this important phenomenon, are briefly discussed. Finally, it will be indicated to what extent the redshift promises to become of importance for the study of cosmic rays.

PDF icon 1711.01693.pdf

and also the paper 'On the Masses of Nebulae and of Clusters of Nebulae' (Astrophys.J. 86 (1937) 217-246):

Present estimates of the masses of nebulae are based on observations of the luminosities and internal rotations of nebulae. It is shown that both these methods are unreliable; that from the observed luminosities of extragalactic systems only lower limits for the values of their masses can be obtained, and that from internal rotations alone no determination of the masses of nebulae is possible. The observed internal motions of nebulae can be understood on the basis of a simple mechanical model, some properties of which are discussed. The essential feature is a central core whose internal viscosity due to the gravitational interactions of its component masses is so high as to cause it to rotate like a solid body.

PDF icon1937ApJ.pdf