How to create a universe

The purpose of this paper is (i) to expound the specification of a universe, according to those parts of mathematical physics which have been experimentally and observationally verified in our own universe; and (ii) to expound the possible means of creating a universe in the laboratory

Explanation and discovery in aerodynamics

The purpose of this paper is to discuss and clarify the explanations commonly cited for the aerodynamic lift generated by a wing, and to then analyse, as a case study of engineering discovery, the aerodynamic revolutions which have taken place within Formula 1 in the past 40 years. The paper begins with an introduction that provides a succinct summary of the mathematics of fluid mechanics

Universe creation on a computer

The purpose of this paper is to provide an account of the epistemology and metaphysics of universe creation on a computer

Joining inner space to outer space

The purpose of this paper is to demonstrate that it is possible, in principle, to obtain knowledge of the entire universe at the present time, even if the radius of the universe is much larger than the radius of the observable universe

The Duality of the Universe

It is proposed that the physical universe is an instance of a mathematical structure which possesses a dual structure, and that this dual structure is the collection of all possible knowledge of the physical universe. In turn, the physical universe is then the dual space of the latter

Possible physical universes

The purpose of this paper is to discuss the various types of physical universe which could exist according to modern mathematical physics. The paper begins with an introduction that approaches the question from the viewpoint of ontic structural realism. Section 2 takes the case of the 'multiverse' of spatially homogeneous universes, and analyses the famous Collins-Hawking argument, which purports to show that our own universe is a very special member of this collection. Section 3 considers the multiverse of all solutions to the Einstein field equations, and continues the discussion of whether the notions of special and typical can be defined within such a collection

Mathematics and explanation in astronomy and astrophysics

The purpose of this paper is to expound and clarify the mathematics and explanations commonly employed in certain notable areas of astronomy and astrophysics. The first section concentrates upon the mathematics employed to represent and understand stellar structure and evolution. The second section analyses two different explanations for the structure of spiral galaxies

Inflationary cosmology and the scale-invariant spectrum

The claim of inflationary cosmology to explain certain observable facts, which the Friedmann-Roberston-Walker models of `Big-Bang' cosmology were forced to assume, has already been the subject of significant philosophical analysis. However, the principal empirical claim of inflationary cosmology, that it can predict the scale-invariant power spectrum of density perturbations, as detected in measurements of the cosmic microwave background radiation, has hitherto been taken at face value by philosophers. The purpose of this paper is to expound the theory of density perturbations used by inflationary cosmology, to assess whether inflation really does predict a scale-invariant spectrum, and to identify the assumptions necessary for such a derivation. The first section of the paper explains what a scale invariant power-spectrum is, and the requirements placed on a cosmological theory of such density perturbations. The second section explains and analyses the concept of the Hubble horizon, and its behaviour within an inflationary space-time. The third section expounds the inflationary derivation of scale-invariance, and scrutinises the assumptions within that derivation. The fourth section analyses the explanatory role of `horizon-crossing' within the inflationary scenario

Cosmology and entropy: in search of further clarity

The concept of cosmic entropy, and the purported need to explain the initial conditions of Friedmann-Robertson-Walker 'Big Bang cosmology', continue to cause confusion within the scientific community. David Wallace's 2010 paper went some way towards disentangling this confusion, but left a number of significant issues unaddressed. The purpose of this paper is to define and resolve these issues. The paper begins by making a clear distinction between the entropy density and the entropy of a comoving volume. The different behaviour of these two quantities in Big Bang cosmology is explained and identified. A second distinction is drawn between the different behaviour of radiative entropy and the entropy of matter, and a third distinction is made between actual entropy and maximum possible entropy. The paper then devotes some attention to the particular issues associated with the entropy of matter, and its relationship to the existence of life and complexity. Wallace's account of Big Bang nucleosynthesis is endorsed, albeit in the context of a more general line of argument, demonstrating that the expansion of the universe generates information in both the radiation content as well as the matter content, and does so without the need for any 'clumping' of matter. The role of stars and galaxies in the cosmic entropy budget is then expounded, the argument concurring and extending that provided by Wallace. In particular, attention is drawn to the eventual evaporation of gravitationally bound systems. However, whilst Wallace accepts black-hole entropy as something of a special case, this paper takes a more sceptical approach to black hole thermodynamics, endorsing and extending recent arguments from Dougherty and Callender. The paper concludes by analysing the role of entropy within inflationary cosmology, identifying the differences and similarities with Big Bang cosmology