Carl Wirtz' article from 1924 in Astronomische Nachrichten on the radial motions of spiral nebulae

TL;DR

This paper discusses Carl Wirtz's 1924 work on the radial motions of spiral nebulae, highlighting its early interpretation of galaxy redshifts as evidence for universe expansion and its historical significance.

Contribution

It presents the first cosmological interpretation of galaxy redshifts as a consequence of universe expansion, based on Wirtz's early 20th-century observations.

Findings

Wirtz's 1924 interpretation of redshift as universe expansion

Historical context of early nebulae research

Current challenges in understanding universe evolution

Abstract

In the year 1924, a paper by Carl Wirtz appeared in Astronomische Nachrichten, entitled 'De Sitter's cosmology and the radial motion of spiral galaxies'. This paper and its author remained largely unnoticed by the community, but it seems to be the first cosmological interpretation of the redshift of galaxies as a time dilation effect and the expansion of the Universe. Edwin Hubble knew Wirtz' publications quite well. The modern reader would find Wirtz' own understanding diffuse and contradictory in some aspects, but that reflected the early literature on nebulae, to which he himself made important contributions. The 100th anniversary provides a good opportunity to present an English transcription to the community, which can be found in the appendix. This anniversary also provokes to ask for the present status of cosmology which many authors see in a crisis. From an observational viewpoint it shall be illustrated that until today there is no consistent/convincing understanding of how the Universe evolved.