Time and Again

Several weeks ago I wrote an essay about time. I made the point that the most popular scientific theory of creation, the “Big Bang Theory”, postulates that time commenced with the creation of matter with the Big Bang. I theorised that perhaps the Big Bang is an artifice that we need to understand creation because of our limitations of perception. This week I’d like to elaborate some more on this topic.

What is the evidence that supports the assumption that the Big Bang occurred? Largely it is threefold.

Firstly is the fact that as our knowledge of the universe increased it became obvious that the universe is expanding. The cosmic explosion that created the universe provided sufficient momentum to expand the universe. Of course some theories predict, that depending on the quantity of matter in the universe the current expansion could possibly be followed by a contracting phase when the universe under the effects of gravity again regresses to a singularity. In order to explain some of the physical characteristics of the universe, proponents of the Big Bang theory also believe that the rate of expansion has not been constant and that the constant rate of expansion we now observe was preceded at the beginning by a period of far more rapid expansion, called inflationary expansion. But put simply, the expansion we observe could have been created by a Big Bang event.

Secondly, the distribution of matter through the universe is consistent with the Big Bang theory. The universe is comprised of a preponderance of lighter elements and a paucity of heavier ones. This is consistent with the Big Bang creation originally of Hydrogen and then through successive processes of fusion caused by gravity as matter aggregated creating the heavier, more complex atoms.

Thirdly the theory predicts that the Big Bang would have caused a huge emission of cosmic microwaves. Scientists have shown that whichever way you look out at the universe there is a consistent level of cosmic microwave background (CMB) at a frequency consistent with what the Big Bang would predict.

So in this respect the Big Bang theory is consistent with some of the problems cosmology has thrown at us. (It also throws up some issues of its own that we won’t be able to address in this short essay.)

But is this the only solution? Well, perhaps not.

Across more than twenty centuries of human cosmological investigation, the possibility that time repeats itself has been powerfully seductive. Forcing the cosmos to begin ex nihilo creates quite a few paradoxes that has caused disquiet among many scientists.

As alluded to above, some scientists explored the possibility of a universe that expanded and then contracted again under gravity to what was called the “Big Crunch” which then recreated a singularity which would then initiate another Big Bang. This would result in a cycling universe. But then it was shown that the accumulation of cosmic entropy would eventually sound the death knell for repeating cosmic cycles.

Then along came string theory. Now, I don’t profess to understand string theory, but bear with me a while so that I can lay out some of its guiding principles. In this way you might come to understand how complex the scientific theories of creation are becoming!

But to begin with string theory seemed to be a simplifying concept. String theory originated from the work of Gabriele Veneziano at CERN. He proposed a new equation to describe the behaviour of the strong nuclear force. (The strong nuclear force, along with the weak nuclear force, gravity and electromagnetic force. is one of the four fundamental forces of the universe.) A few years later, Veneziano’s equation was reinterpreted and shown to describe particles as vibrating strings. This simplified our concepts about particles with this technique enabling the known particles to be all described in this way.

But with this came a substantial trade-off. String theory might have provided a simpler way of describing particles and it gave some hope to physicists wanting to develop a theory of quantum gravity, but the theory couldn’t work in our conventional four-dimensional universe. To propagate the theory scientists had to add “more space”. The price they had to pay was to add another seven invisible dimensions to reality.

Now I will forgo the temptation to attempt to explain the mathematics involved here! Adam Frank, the Professor of Astrophysics at the University of Rochester makes this comment:

String theory is highly mathematical in a way that would make Pythagoras smile. Its levels of abstraction reach far higher than those of general relativity or ordinary quantum physics and require a serious leap of theoretical faith. String theory can recover known particles and forces only if the universe has more space than we perceive, implying a cosmos with so-called extra dimensions. In addition to the three dimensions we are familiar with, height, breadth and width, string theory requires the universe to possess seven extra dimensions of space. The equations fail with anything less.

In the exploration of string theory’s remarkable mathematical terrain physicists found that in addition to vibrating one-dimensional strings, multidimensional strings were also possible. These constructs were called “branes”. (This colloquialism was derived from the two-dimensional version which was portrayed as a membrane.)

This notion was further developed by Neil Turok and Paul Steinhardt in 1999. They imagined three dimensional branes existing side by side in multidimensional space. If we viewed our universe as one of these branes, they showed that three of the fundamental forces mentioned above would be restricted to this particular brane and only one, gravity, would apply throughout the multidimensional space which was called the “Bulk”. So in effect the multidimensional space was inhabited by multiple (perhaps infinite) universes. Now because gravity exists throughout the entire Bulk, each universe exerts force on its neighbour.

In their popular book, Endless Universe, Steinhardt and Turok wrote:

The picture we had in mind was of two widely separated, parallel branes stretching to infinity in three directions. A tiny force existed between the two branes, causing them to attract and move very slowly towards each other along the fourth dimension over a long, perhaps infinite period of time. The force grew ever stronger as they approached, speeding their motion toward the collision. At the bang, the kinetic energy of the branes would be converted into hot radiation.

Steinhardt and Turok then went on to show how what then transpired inside our brane as a result of the collision of branes played out exactly like the conventional Big Bang theory. Consequently it provided just as convincing a solution to the issues of an expansionary universe, the distribution of matter and the cosmic background radiation.

To make a long story short, Steinhardt and Turok eventually embellished their theory into a cyclic model. In their model, after collision the branes separate and the space within the branes expand. Trillions of years after the collision gravity again expresses itself and the branes start to come together again and the whole cycle is repeated. Interestingly it is the space between the branes that expands and contracts. Under these circumstances the entropy within the brane is maintained constant and therefore the model doesn’t suffer from the ever increasing entropy that doomed other cyclic models.

If Steinhardt and Turok’s model does in fact describe our universe time is infinite. Unlike the Big Bang which postulates that time commences when the three spatial dimensions are created, the Steinhardt and Turok model allows no beginning or ending of time. For each successive collision there is a before and an after.

Among other deities, the ancient Hindus worshipped the god Shiva. The universe was a manifestation of Shiva’s dance. In this myth, endless cycles of creation and destruction arise in response the Shiva’s cosmogenic choreography. A remarkable aspect of the Hindu imagination was its attempt to grasp the impossibly large numbers associated with the cycles of cosmic history.

This is explained by Adam Frank (quoted earlier):

One cosmic turn of creation and destruction was called a mahayuga and was reckoned to last 12,000 gods’ years, with each divine year being the equivalent of 360 years. Thus each cycle lasted more than four million solar years. A kalpa was a single day in life of the divine godhead, Brahma (a deity below Shiva) and it consisted of two thousand of these mahayugas There would be many Brahmas, each destined to die and be reborn. The lifetime of a single Brahma lasted one hundred Brahma years, or more than three hundred trillion human years. In these vast stretches of time we can clearly see an early attempt, written in myth to embrace the intuitive sense that creationless cosmic histories must stretch across vast horizons of time.

Maybe it’s my reaction to multiverses and branes and space of eleven dimensions but if we have to go to such lengths to explain cosmology and time I find it more attractive to think of Shiva’s marvellous dance!

After all, theoretical concepts like branes, multiverses and multidimensional space are mere allegories designed to remove scientific riddles. There is no evidence that such things exist. They have been conjured up to help us explain the world. In this respect they are little different from any other creation myth. Dance on Shiva!

[After this my readers are probably bored by the subject of time. But if I am tempted to broach the subject again, I am inclined to write a piece suggesting that time doesn’t really exist and that it is another manifestation of the basic dualism problem that Buddhists have been considering for two thousand years!]