Most of these introductory articles are exracted from Volume I of the Single Monad Model of the Cosmos: Ibn al-Arabi's View of Time and Creation... more on this can be found here.

## Summary of Modern Theories of Cosmology

Since Copernicus' time, our view of the cosmos has grown both larger and more accurate. It is not our purpose here to explain the modern complicated theories of cosmology, but simply to summarize the present picture of the cosmos as seen by scientists. Our modern picture of the cosmos dates back only to 1924, when Edwin Hubble showed that our galaxy is not the only one in space; many of the faint spots of light that we see in the sky are in fact other galaxies as large as our own, but we only see them so small because they are extremely far deep in space.

Due to the force of gravity, everything in the sky is moving or orbiting around some point in space. The moon orbits around the earth, and the earth and other planets orbit around the sun, which also orbits - along with other hundreds of thousands of millions of stars - around the centre of the Milky Way galaxy, which is in turn one of thousands of millions of galaxies all flying through the vast distances of space.

In order to give a clear spatial view of this immense universe, it is better to use big units of distance instead of using big numbers. The best accepted units of distance in cosmology are the 'light year' (9,500,000,000,000,000 meters), which is the distance travelled by light in one year, and the 'parsec', which equals 3.26 light years. Light travelling at 300,000 km/sec can go seven times around the earth (which has a circumference of approximately 44,000 km) in one second, but it takes 8.33 minutes to reach us from the sun (150,000,000 km). Proxima Centauri, the nearest star to us apart from the sun, is about 4.24 light years away. Our galaxy, like most other galaxies, is a collection of about 200 billion stars plus thousands of clusters and nebulae that form together a disc of more than 100,000 light years in diameter, and that is about 15,000 light years thick. The nearest galaxy to us lies in the Andromeda constellation, and it is about 2.9 million light-years away. Then galaxies are grouped in somewhat irregular clusters that greatly differ in size between millions to hundreds of millions of light years. The most distant objects discovered so far are about 13 billion light years away. These numbers above are simply approximate, just to give an idea of where we are (Hartmann 1990: 413).

It is now also well established that everything in the world is moving: nearby stars have proper motion, because they are pulled towards the centre of the galaxy, and galaxies are moving away from us, because the universe is expanding. On the other hand, and despite these various motions, the universe doesn't have a centre or edges. It is hard to imagine, but the universe is contained or curved around itself so that if you fly straight in one direction and keep moving in a straight line you will one day, if you could live long enough, come back from the opposite direction to the same point (supposing no gravitational fluctuations), just as it would happen to a person travelling around the earth.

The stars that we see in the sky are, just like our sun, huge nuclear fusion reactors that are constantly converting hydrogen into heavier elements and hence producing heat and light. But not all stars are the same: some are big and some are small; some are young and some are old; some are bright and some are faint. Also, many stars are dying and many others are born all the time in a process of very complicated evolution (Seeds 1990: 134-281).

So how is all this explained according to the new cosmological theories? We can't discuss here all the different theories in physics and cosmology, but we want to note a quick summary of the basic principles of the different models of the cosmos so that we can understand the potential importance of the 'Single Monad model' which we are going to propose in the last chapter of this book, based on Ibn al-Arabi's unique understanding of time and his famous theory of the oneness of being.

Summary of Modern Theories of Cosmology:

After the amazing discoveries and the enormous amount of data obtained by telescopes and space shuttles, and with the success of the theories of Relativity and Quantum Mechanics, scientists tried to build new cosmological models to explain the structure and origin of the universe based on the new information. We shall give here a very short summary of the major theories of cosmology that have developed recently.

Scientists up to the beginning of the twentieth century believed in a stationary universe outside the solar system, but this was soon proven to be wrong. Actually the same theory that Einstein first tried to make fit a steady universe and fixed stars later proved that the universe is expanding. This implied that the universe had started at one moment, about fifteen billion years ago, from a very small point, but with very high density, and then it expanded to its present state. This was called the 'Big Bang', and many cosmological models were developed based on this view (Narlikar 1995: ch.2, ch.5).

The 'Steady State' theory tried to explain the expansion of the universe by supposing a continuous creation of matter that filled the space produced by the expansion, but the discovery of cosmic microwave background radiation in 1965 by Penzias and Wilson caused the Steady State model to be completely discarded. The background radiation was interpreted as the faint afterglow of the intense radiation of a 'Hot Big Bang', which had been predicted by Alpher and Hermann back in 1949, although some people also attribute it to Gamov back in 1946 (Dolgov 1990: 11).

The problem with the background radiation was that all measurements showed it to be very uniform in all directions. This isotropy of the background radiation was a riddle because with homogeneity no stars or galaxies could be produced (Taylor 1993: 194). It was only in 1992 that NASA's Cosmic Background Explorer satellite (COBE) detected the first anisotropies in this background radiation: one part in a hundred thousand, which may indicate the seeds from which galaxies formed (Schewe 1992: 1).

The Big Bang model was very good in explaining many of the observations, yet on the other hand there were many contradictions (Linde 1990: 4). Many of these theoretical contradictions were resolved by the 'inflationary scenario' devised by Alan Guth in 1979. Guth looked at a very early stage in the development of the universe from about 10-32 to 10-43 of a second after the initial creation. During this period matter was in very highly excited states, causing the most extreme conditions of high density and pressure which made the cosmos expand exponentially, filling the universe with an intense dense fire of particles and photons (Linde 1990: 42).

In classical (Newtonian) mechanics, one could predict the behaviour of a system if one exactly knew its initial state. But in Quantum Mechanics, we can only calculate the probability of how the system will evolve (White 1966: 29). In either case, however, the main problem in cosmology is to determine the initial state that the laws should be applied to. One successful approach to get round this problem is to work backwards by using the observed properties of the universe to deduce what it was like in an earlier state.

The problem with the inflationary theory is that, in order for inflation to have occurred, the universe must have been formed containing some matter in a highly excited state, but the next question is why this matter was in such an excited state. To overcome this, some scientists tried to apply Quantum Mechanics to the whole universe, and the result was the theory of Quantum Cosmology.[1] This may sound absurd, because typically large systems (such as the universe) obey classical, not quantum, laws. Einstein's theory of General Relativity is a classical theory that accurately describes the evolution of the universe from the first fraction of a second of its existence up to now. However it is known that General Relativity is inconsistent with the principles of Quantum Theory, and is therefore not an appropriate description of the physical processes that occur at very small length scales or over very short times. To describe such processes we require the theory of Quantum Gravity.

In non-gravitational physics, the approach to quantum theory that has proved most successful involves mathematical objects known as 'Path Integrals' that were introduced by the Nobel Prize winner Richard Feynman. In the Path Integral approach, the probability that a system in an initial state A will evolve to a final state B is given by adding up a contribution from every possible history of the system that starts in A and ends in B. For large systems, contributions from similar histories cancel each other in the sum and only one history is important. This history is the history that classical physics would predict. At any moment, the universe is described by the geometry of the three spatial dimensions as well as by any matter fields that may be present. Given this data, one can in principle use the Path Integral to calculate the probability of evolving to any other prescribed state at a later time. However, this still requires knowledge of the initial state.

Quantum Cosmology is a possible solution to this problem. In 1983, Stephen Hawking and James Hartle developed a theory of Quantum Cosmology which has become known as the 'No Boundary Proposal'. In practice, calculating probabilities in Quantum Cosmology using the full Path Integral is formidably difficult and an approximation has to be used. This is known as the 'semi-classical approximation', because its validity lies somewhere between that of classical and quantum physics. In the semi-classical approximation, one argues that most of the four-dimensional (spacetime) geometries occurring in the Path Integral will give very small contributions to the Path Integral and hence these can be neglected, so we can deal only with three dimensions (space). The Path Integral can be calculated by just considering a few geometries that give a particularly large contribution. These are known as 'Instantons' (from 'the instant', because it aims at omitting time, so it is like a snapshot that takes into account only the three coordinates of space), which describes the spontaneous appearance of a universe from literally nothing. In this way we don't have to think about the cosmos as something that takes place inside some bigger spacetime arena. Once the universe exists, Quantum Cosmology can be approximated by General Relativity, so time appears.

Research in these areas is still ongoing, but one of the many outstanding problems in trying to construct a quantum field theory of gravitation concerns the appropriate interpretation of quantum states for configurations that make no overt reference to 'time'. We shall see by the end of this book that Ibn al-Arabi's understanding of time could be a key to eliminating these peculiarities, because he simply views the world as an eternal existence that is perpetually being re-created. He also unified space and time in a manner that has apparently never been thought of before or since.

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[1] For more information about the principles of quantum cosmology, see: Linde, A. D. (1990), Inflation and Quantum Cosmology, San Diego: Academic Press: chapter 3 [Quantum Cosmology and the Stochastic Approach to Inflation].