Related papers: Slipher and the Nature of the Nebulae
By 1917, V.M. Slipher had singlehandedly established a tendency for 'spiral nebulae' to be redshifted (21 out of 25 cases). From a modern perspective, it could seem surprising that the expansion of the universe was not announced at this…
Vesto Melvin Slipher was the first astronomer to clearly define the factors that determine the "speed" of a nebular spectrograph. This brief historical summary recounts the way these ideas developed and how Slipher's early work on galaxy…
English and Spanish translations are provided for Fritz Zwicky's seminal article on "The Redshift of Extragalactic Nebulae", published in German in Helvetica Physica Acta in 1933…
A new contextualised reading of Fritz Zwicky's 1933 article ''The redshift of extragalactic nebulae'' about the virial analysis of the velocity dispersion of galaxies in the Coma cluster leads to a reconsideration of the traditional…
Priority in the discovery of the velocity-distance relationship may be shifting from Edwin Hubble to Georges Lemaitre, but any reassessment of credit must also consider the contributions of Vesto Slipher. Not only were his spiral galaxy…
When V. M. Slipher gave the 1933 George Darwin lecture to the Royal Astronomical Society, it was natural that he spoke on spectrographic studies of planets. Less than one-sixth of his published work deals with globular clusters and the…
In 1929 Zwicky proposed a tired light theory to interpret the Hubble law (Hubble 1929). The key of the tired light theory is to interpret the observed redshift of galaxy as the non-Doppler effect. But the derivation of the dark matter in…
A brief history of the discovery of the expanding universe is presented, with an emphasis on the seminal contribution of VM Slipher. It is suggested that the well-known Hubble graph of 1929 could also be known as the Hubble-Slipher graph.…
Redshift observations of galaxies outside the Local Group are fairly common in extragalactic astrophysics. If redshifts are interpreted as arising from radial velocities, these must be corrected by the contamination of the solar motion. We…
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…
Although the extragalactic nature of quasars was discussed as early as 1960, it was rejected largely because of preconceived ideas about what appeared to be an unrealistically high radio and optical luminosity. Following the 1962…
Celestial observations often exhibit inexplicable planetary dependencies when the timing of an observable is projected onto planetary heliocentric positions. This is possible only for incident, non-relativistic streams. Notably, the…
Carl Lampland was the first to observe a comet in the infrared, a feat little known today because he failed to formally publish his data. I have retrieved the radiometry of this comet, C/1927 X1 (Skjellerup-Maristany), taken in broad…
Of the first two relativistiv world models, only the one by de Sitter predicted redshifted spectra from far away astronomical objects. Slipher's redshifts therefore seemed to arbitrate against Einstein's model which made no such…
The most intriguing question of modern astronomy is the question of our Universe formation. The Hubble diagram analysis with Type Ia Supernovae (SNe Ia) is widely used to estimate the cosmological parameters with high accuracy. The…
Over the past century a succession of five different independent astronomical phenomena have been discovered, each appearing to be the result of a common underlying cause that also produces an unaccounted-for acceleration that is: quite…
Arthur Stanley Eddington was one of the leading astronomers and theorists of his generation and a prominent proponent of the general theory of relativity. Yet when his former assistant Georges Lemaitre sent him a paper in 1927 suggesting…
A massive galaxy cluster can serve as a magnifying glass for distant stellar populations, with strong gravitational lensing exposing details in the lensed background galaxies that would otherwise be undetectable. The MACS J0416.1-2403…
A Fourier transform analysis of 2.5 million spectra in the SDSS survey was carried out to detect periodic modulations contained in their intensity versus frequency spectrum. A statistically significant signal was found for 223 galaxies…
We show that the time-dependent Doppler effect should induce measureable deviations of the time history of the projected orbit of a star around the supermassive black hole in the Galactic center (SgrA*) from the expected Keplerian history.…