August General Meeting Report
Guest Speaker Dr Bart Pindor, The University of Melbourne.
His subject: “The Evolution of the Universe”

In introducing our guest for the evening, the Chairman Vice President Jim Pollock said, “...you can see from the title of tonight’s talk that Dr Pindor does not go for halve measures”. It is a huge subject, stretching over aeons, an open subject with no end in sight. For a final verdict (not unlike the Global Warming debate or the current financial crisis) the jury is still out.
Two generations of us have grown up in the shadow of the “Big Bang” theory of creation. After being “confirmed” by numerous discoveries and tests in that time, that theory, it seems, is suddenly becoming aware of little clouds on the horizon. Perhaps a more appropriate title for the talk should have been “the Evolution of our Understanding of an evolving Universe”.
With a series of illuminating slides Dr Pindor led us into the subject: Edwin Powell Hubble (1889-1953) building on the work on Vesto Slipher, showed in 1929 that the Universe is expanding and suggested that it consequently must have had a definitive origin. He recognised that, while some of those fuzzy patches of light then known as nebulae are gas clouds within our Milky Way, others seemed to be galaxies in their own right. He classified their structures and eventually identified Cepheid Variable stars in some of them. On hand of those he, with his assistant Milton Humason, established the relationship between the distance of those galaxies and the redshift of their light as they move away from us (a short diversion into Real Estate helped Dr Pindor in his demonstration). This relationship has became known as the Hubble constant, or Hubble parameter (as it may actually not be constant), originally estimated at between 40 and 80km per second per Megaparsec. The inverse of the Hubble constant (Hubble Time) then becomes the measure of the age of the Universe. Fred Hoyle {1915-2001 (knighted in 1972)} who in the 1940-50s was the leading light in the team (B2FH) that explained how the heavier elements are manufactured inside stars, picked up the thread and in the 1960s with a tour de force three week lecture course played a major part in explaining how (if there had been a big bang) the lighter elements would have been “cooked” in the first few minutes (see Universal Abundance). Sir Fred originally coined the expression “Big Bang” in a dismissive, derogatory sense and, together with his “Steady State” model of the Universe, he may yet be vindicated in that belief. But back then, when Robert Dicke of Princeton University recognised the cosmic noise that so troubled Arno Penzias and Robert Wilson in 1964 as a remnant of the big bang (predicted in 1946 by George Gamow of alpha beta gamma theory fame), everybody jumped on the big-bang bandwagon.
By the 1980s scientists began to worry about the “little clouds” on the astronomical horizon. Improved measurement techniques confirmed that galaxies did not strictly obey Newton’s Law of gravitation. There appeared to be a massive missing mass mystery. Everyone started to look for all sorts of exotic particles to make up the deficit. Collectively it was called Dark Matter, assumed to be retained in extensive halos around every galaxy, up to 10 times the mass of its visible matter. Even worse, in giant clusters of galaxies this figure rises to 30. Now new X-ray and Infrared Space Telescopes have added a new twist to the confusion by finding indications that the expansion of the Universe shows no sign of slowing down, but is actually accelerating. Dark Energy was invented to account for this; a re-incarnation of Einstein’s gravity balancing lambda component (see A Twist in the Tale). The stage is set for a break-through in our understanding of Space-Time and the underlying structure of Nothingness.

A thoroughly enjoyable and refreshing romp through cosmology The vote of thanks was given by Jim Pollock with due acknowledgement of the changing landscape of astronomy. In a break with tradition Jim presented Dr Bart Pindor as a token of our appreciation with a gift voucher for a book of his choice, to general acclaim.
A Klink