Cosmology Notions

Dear Chris,
Attached is my response to the Insomniac Cosmologist article by Dave Gordon in the April 04 issue of Canopus.
Alec Jamieson.

I was very interested to read Dave Gordon’s Insomniac Cosmologist article in the April 2004 issue of Canopus. Taking notice of what goes on in the sky by way of an interest in astronomy is what leads us on to more questions and more understanding of the universe that we find ourselves living in.

The Insomniac Cosmologist article covered several issues, each of which provide food for thought and will perhaps draw separate responses. This response is confined mainly to the dissatisfaction expressed in the article with the big bang theory and the concern that it may be ideologically motivated.

I think that many people including cosmologists, who support the big bang theory, are not entirely happy with it. A consequence of being at the frontier of knowledge is that there are sometimes perplexing gaps in that knowledge. The gaps in a theory are not necessarily fatal flaws; they just have to await new ideas while progress is made in other areas of the theory.

Forget the galaxies. Cosmologists have yet to account for the observed masses of the elementary particles of nature formed in the big bang. This requires very intricate mathematical analysis to guide the thinking in a physics environment that is totally alien and unfamiliar to our everyday experience. Along the way, interested lay observers of these efforts get a bit left behind by simplified descriptions of the work being done.

Normally, something that explodes exists before the explosion, and then it explodes, throwing debris outward. Trying to visualize the progress of an explosion from a starting point of zero size is quite a slippery concept.

Other features of big bang cosmology like the beginning of time (presumably there could be no countdown to the big bang), expansion of space, and the presence of the background microwave radiation are all phenomena that make a difficult mix of concepts for anyone to grasp.

The moral so far is that astronomy should keep astronomers awake at night, but the loose ends of big bang cosmology should not!

In defence of the scientists who are grappling with the innermost workings of big bang theory, I would like to give an illustration of how far back they are attempting to push the curtain of time towards the instant of the big bang.

From the first ten thousandth of a second (10^-4 s) after time zero they have a pretty good handle on things. The problem is to account for what happened, and why, from the first 10^-4 second back to time zero. Theoretical work has been going on down to a scale of 10^-33 metre and 10^-43 second after time zero, known as the Planck length and the Planck time respectively. The Planck length is derived from the gravitation constant, Planck’s constant and the speed of light. The Planck time is the time it takes light to travel the Planck length. In layman’s terms these tiny values of distance and time leave very little room or time for any physics to happen.

Just as the light-year masks the vast distances between the stars, the exponential notation used above masks the enormity of the extrapolation downwards from the physics of our familiar world to the conceptual world of the Planck length and the Planck time where the origin of the big bang is being sought. A comparison of the Planck length with a proton, the nucleus of a hydrogen atom, helps to put these large exponent numbers into perspective. If a Planck length object (10^-33 m) is magnified to the size of a mote of dust a thousandth of a millimeter in diameter (10^-6 m) it would have to be magnified 10²⁷ times. If the same magnification were applied to a proton with diameter of about 10^-15 m, the magnified proton would have a diameter of 10¹² metres. That is a diameter of a billion km, which is roughly the diameter of the asteroid belt between the orbits of Mars & Jupiter.

With this fantastic microscope of imagination and mathematics, theoretical physicists and mathematicians are searching for extended theories of physics that will stand up to mathematical scrutiny at the scale of a dust mote beside a proton a billion km across.

This gives an indication of how drastically the conditions of our physical world could differ from the conditions thought to prevail near the time of the big bang, and how great is the effort that it takes to increase understanding in this branch of cosmology. In view of the huge collective effort that is the price paid for present knowledge, and human nature being what it is, I believe that there is very little possibility of ideologically preferred ideas obscuring truth for very long.

In 1948 the steady-state theory was put forward. Subsequent observations from radio astronomy on the distribution of extragalactic radio sources conflicted with a basic principle of the steady state theory, which holds that all large-scale properties of the universe must be constant in time. The discovery of the microwave background radiation, which in principle is slowly fading, also conflicted with the basic concept of a steady-state universe.

The accumulation of evidence and theory is nudging us in the direction of the hot big bang model of the origin of the universe. Getting a classical camel through the classical eye of a needle is an enterprise doomed to failure, but with help from the speed of light, the theory of relativity and some quantum tunneling, who knows what may emerge from this brew of exotic physics.

As the frontier of time and space is pushed back towards absolute zero, it may be that physics will have to be stripped to its most basic element in order to co-exist with the extreme constraints of space and time close to absolute zero. Perhaps, at time zero it will be found that all of physics and cosmology is reduced to a single photon of such great energy that it can give rise to all particles, all forces and all history in the universe to be.

It seems fitting that the big bang event that we have been speculating upon is not the first or the last. Like intersecting ripples from raindrops falling on water, we may one day understand effects in our universe that give hints of other big bang events in a greater Universe that is infinite in both space and time.

Alec Jamieson.