Related papers: The Great Debate
This is a very comprehensible review of some key issues in Modern Cosmology. Simple mathematical examples and analogies are always used, whenever available. The starting point is the well know Big Bang Cosmology (BBC). We deal with the…
Multiverse scenarios in cosmology assume that other universes exist "beyond" our own universe. They are an exciting challenge both for empirical and theoretical research as well as for philosophy of science. They could be necessary to…
A cosmological model is proposed which uses a causality argument to solve the homogeneity and entropy problems of cosmology. In this model a chronology violating region of spacetime causally precedes the remainder of the Universe, and a…
There are long standing questions about the Big Bang What were its properties? Was there nothing before it? Was the universe always here? Many conceptual issues revolve around time. This paper gives a novel model based on McTaggarts…
The large-scale structure of the Universe is well approximated by the Friedmann equations, parametrized by several energy densities which can be observationally inferred. A natural question to ask is: How different would the Universe be if…
We have created a show about the Solar System, freely available for both planetariums and home viewing, where objects in space are represented with sound as well as with visuals. For example, the audience listens to the stars appear above…
The distribution of galaxies up to a distance of 200 Mpc (650 million light-years) is flat and shows a structure like a shell roughly centered on the Local Supercluster (Virgo cluster). This result clearly confirms the existence of the…
We investigated the evolution of clusters of galaxies using self-consistent $N$-body simulations in which each galaxy was modeled by many particles. We carried out simulations for about 20 cases using different initial conditions. In all…
For more than a half century cosmologists have been guided by the assumption that matter is distributed homogeneously on sufficiently large scales. On the other hand, observations have consistently yielded evidence for inhomogeneity in the…
We revise the statistical properties of the primordial cosmological density anisotropies that, at the time of matter radiation equality, seeded the gravitational development of large scale structures in the, otherwise, homogeneous and…
We develop a unified, dynamical-systems narrative of the universe that traces a continuous chain of structure formation from the Big Bang to contemporary human societies and their artificial learning systems. Rather than treating cosmology,…
This paper enlarges classical syllogistic logic with assertions having to do with comparisons between the sizes of sets. So it concerns a logical system whose sentences are of the following forms: {\sf All $x$ are $y$} and {\sf Some $x$ are…
In the light of his recent (and fully deserved) Nobel Prize, this pedagogical paper draws attention to a fundamental tension that drove Penrose's work on general relativity. His 1965 singularity theorem (for which he got the prize) does not…
This is the written version of an invited review talk for the 13 Feb 2004 AAAS Meeting in Seattle. The talk's goal is to present a philosophical view of extragalactic astronomy as it applies to the sub-field of galaxy evolution. The talk is…
Understanding how galaxies evolved from the early Universe through cosmic time is a fundamental part of modern astrophysics. In order to study this evolution it is important to sample the galaxies at various times in a consistent way…
This is the transcript of a lecture given at UMass-Lowell in which I compare and contrast the work of Godel and of Turing and my own work on incompleteness. I also discuss randomness in physics vs randomness in pure mathematics.
General relativity predicts a singularity in the beginning of the universe being called big bang. Recent developments in loop quantum cosmology avoid the singularity and the big bang is replaced by a big bounce. A classical theory of…
It is commonly assumed that the energy density of the Universe was dominated by radiation between reheating after inflation and the onset of matter domination 54,000 years later. While the abundance of light elements indicates that the…
This new book by cosmologists Geraint F. Lewis and Luke A. Barnes is another entry in the long list of cosmology-centered physics books intended for a large audience. While many such books aim at advancing a novel scientific theory, A…
As AI systems are used to answer more difficult questions and potentially help create new knowledge, judging the truthfulness of their outputs becomes more difficult and more important. How can we supervise unreliable experts, which have…