Can we definitively know the global structure of spacetime? This is a good question. It is one that is actively discussed in the area of the philosophy of modern physics.1,2
However it is a question that highlights the fundamental weakness of cosmology and hence of cosmogony. (Cosmology is the study of the structure of the cosmos whereas cosmogony is the study of the origin of the universe.) That weakness is the inherent inability to accurately construct any global cosmological model, i.e. a model that accurately represents the structure of the universe at all times and locations. The reason for this is underdetermination.3
“There seems to be a robust sense in which the global structure of every cosmological model is underdetermined.”1
In the philosophy of science, underdetermination means that the available evidence is insufficient to be able to determine which belief one should hold about that evidence. That means that no matter what cosmological model one might conceive of, in an attempt to describe the structure of the universe, every model will be underdetermined. Or said another way, no matter what amount of observational data one might ever (even in principle) gather, the cosmological evidence does not force one particular model upon us. And this underdetermination has been rigorously proven.1 Continue reading
—or, blinded by big bang blackness
The origin of our universe is a vexing problem for the atheist. The very state of the observable universe today presents serious problems for them, as it demands a Creator. Why did the universe begin in such an organised state, where laws are finely tuned for life to exist, and where irreversible processes occur producing the forward march of time?
In thinking on the nature of the universe and our existence within it, the Greeks developed the philosophies of rationalism1 and empiricism2, two different approaches they believed could determine truth from the world. The former involved deduction,3 and the latter, induction.4 No reference to a Creator God was considered relevant.
The modern cosmologist, one who attempts to explain the origin of a rational universe, with laws derived from observation, is one who believes he can, by inductive reasoning alone, discover its origin without the Creator.
The atheists say the rational mind concludes that there is no God, therefore the universe is the outcome of pure materialism.5 Then how do we explain how the universe came to be? How do we, by induction alone, explain the origin of the laws of physics? And how do we test if our explanations are correct? These are fundamental epistemological6 questions that need to be answered. Continue reading
The Standard Model of particle physics (SM) has been very successful at describing the elementary particles and the forces that bind them together. However, the Standard Model presents some significant problems for big bang theorists. This is because the SM does not contain any Dark-Matter particles, and the neutrinos in it are described as exactly massless. Which means that in its present form, it is in clear contradiction with the big bang model as required by various observations.
Those observations have led to the need to include Dark Matter in the standard (ΛCDM1) big bang model, particularly during the period of nucleosynthesis, just after the big bang beginning when the light elements were allegedly formed from hot hydrogen. Therefore, the Standard Model of particle physics is in stark disagreement with the requirements necessary for the formation of the first elements in the alleged big bang.
Where are the Dark-Matter particles?
All challenges to the standard ΛCDM big bang model have been met and overcome, so far, by assuming ‘unknowns’ particularly Dark Matter and Dark Energy, wherever and whenever needed. Astronomical observations have led big bang astronomers and cosmologists to look for these new unknown Dark-Matter particles to solve many of their problems resulting from such observations; for example, the formation of stars, galaxies and galaxy clusters, the testing of the big bang model with type Ia supernova measurements, the angular power spectrum of the CMB anisotropies, galaxy rotation curves, and in particular, as focussed on here, Big Bang Nucleosynthesis (BBN).2 Continue reading
In 1929 Edwin Hubble published his observations of the redshift and distances of nearby galaxies. Hubble observed in the light from most of those galaxies that the spectral lines were shifted towards the red end of the spectrum as compared to a local laboratory source of the same atomic gas species. From this he interpreted that it was a Doppler effect (ie. due to the motion of the source), where the galaxies were receding from us, the observer. Thus the idea of the expanding universe was founded.
Expanding universe with us at the centre. The galaxies are moving away from us at the same rate in every direction.
But one other important idea came from those same observations. He observed roughly the same redshift in light from the galaxies as a function of distance in every direction he looked. This became known as the Hubble law, which is the basis for the standard cosmology today–the big bang model. But the fact that this was in every direction and that the proportionality between the redshift and distance was the same in every direction meant that it looked to him like we, that is, our galaxy, was at the centre of the Universe. This is because the galaxies were moving away in a spherically symmetric way, putting us at the centre. This view of the Universe then would look something like the image in the figure on the right. Continue reading