Michael L. Smith

By Ahmet M. Öztaş and Michael L. Smith

Part of the book: Aspects of Today's Cosmology

By Michael L. Smith and Ahmet M. Öztaș

Astronomers continue the search for better a Hubble-Lemaitre constant, H0, value and other cosmological parameters describing our expanding Universe. One investigative school uses ‘standard candles’ to estimate distances correlated with galactic redshifts, which are then used to calculate H0 and other parameters. These distance values rely on measurements of Cepheid variable stars, supernovae types Ia and II or HII galaxies/giant extra-galactic HII regions (GEHR) or the tip of red giant star branch to establish a distance ‘ladder’. We describe some common pitfalls of employing log-transformed HII/GEHR and SNe Ia data rather than actual distances and suggest better analytical methods than those commonly used. We also show that results using HII and GEHR data are more meaningful when low quality data are discarded. We then test six important cosmological models using HII/GEHR data but produce no clear winner. Groups utilising gravitational waves and others measuring signals from the cosmic microwave background are now at odds, ‘tension’, with those using the SNe Ia and HII data over Hubble-Lemaitre constant values. We suggest a straightforward remedy for this tension.

Part of the book: Cosmology 2020

By Firmin Oliveira and Michael L. Smith

Several recent attempts to observe dark matter with characteristics similar to atomic or subatomic particles as Weakly Interacting Massive Particles (WIMPs) have failed to detect anything real over a wide energy range. Likewise, considerations of large, non-emitting objects as the source of most dark matter fall short of expectations. Here we consider the possibility that massless gravitons suffering slow redshift may be responsible for the properties of spiral galaxies attributed to dark matter. Particles such as gravitons will be extremely difficult to directly detect; the best we can envision is measuring this influence on stellar and galactic motions. Since the motions of stars and galaxies are non-relativistic, we can apply our idea to describe the expected large-scale motions using only Newtonian mechanics. Using our assumption about the importance of the graviton, we here describe the well-known Tully-Fisher relationship of spiral galaxies without resorting to hypothesizing exotic WIMPs or invoking modifications of Newtonian dynamics (MoND).

Part of the book: Dark Matter

By Michael L. Smith

Part of the book: Dark Matter

By Michael L. Smith, Abdullah Alsakka and Ahmet M. Öztas

The Standard Model (ΛCDM) of cosmology neither estimates the current Milky Way location nor predicts any future position, failing the scientific test of accurate prediction. We analysed data from the 1701 SNe Ia Pantheon+ collection combined with the Tip of the Red Giant Branch (TRGB) emissions to estimate the Hubble constant. We wrote Python codes and saved our results, the SNe and TRGB data as files in GitHub, github.com/Abdullah-Alsakka/About-Transforming-Data. We present the shortcomings of correlations employing the distance modulus (μ) often used for analyses supporting ΛCDM models. The associated standard deviations are also fatally flawed; incorrectly estimating Ωm and ΩΛ using the ΛCDM correlation; we better estimated parameters using DL and σ values. We investigated the Rh=ct model, the Einstein-deSitter model and our ArcTanh model comparing results against the ΛCDM model. There was little difference in the goodness-of-fit between the Rh=ct and our ArcTanh model; both correlated the data better than the ΛCDM model. The ArcTanh model presented a H0≥ 70 km s−1Mpc−1 agreeing with the Riess group. The ArcTanh model presented the smaller values for Ωm, than the ΛCDM model agreeing with BBN calculations. The ArcTanh model also supports the quasi-Euclidean not strictly Euclidean spacetime geometry of the ΛCDM model. Our results and the ability to predict the future location of our Milky Way are evidence that our analytical technique is more valuable than many current methods.

Part of the book: Cosmology Research