Understanding the universe around us
Professor George Ellis is one of South Africa's A Rated scientists. Based at the University of Cape Town's Mathematics department he
continues to challenge and influence world thinking on the universe. In an eight chapter
text now available on the Internet, he delves into "The Universe Around Us:
An Integrative View Of Science And Cosmology." Excerpts from this appear below. Visit
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Cosmology is the science that studies the physical structure of the Universe.
Building on the results of other sciences (particularly physics and
astrophysics), it has led to major new understandings about the nature and
evolution of the matter around us; and this in turn has led to an understanding
of the physical conditions that make life possible on earth. In particular it
has led us to understand:
* There was a hot early phase to the universe when all that existed were
particles and radiation
* The universe is presently expanding, and indeed this expansion seems to be
speeding up
* What we see is just a small fraction of all there is: the universe is
dominated by dark matter
* We can detect the black body relic radiation of the hot big bang
* Huge structures like clusters of galaxies grew our of small inhomogeneities in
the early universe
* The part of the universe we can see is limited because of the existence of
visual horizons
We can characterise some of the big questions that have concerned humanity
since the dawn of consciousness, as follows (cf. [1]):
* The nature of the physical Universe: What is it made of and how does it
work?
* The question of creation: How do things originate?
* The issue of the final state: What will happen in the end?
* The place of humanity in the Universe: How does this all relate to us?
* The meaning of existence: What is the purpose of it all?
This text looks at the way we attain scientific understanding and then at the
physical foundations of the structures in the universe, including life. Then it
discusses the nature, history, and future of the expanding universe, emphasizing
on the one hand what is well-known and on the other what is not known, or may
even be unknowable.
In PART I (`Issues and Foundations') the major questions
which are considered on this text - the scope of the discussion are discussed. It is concluded
by Chapter 2, which outlines the approach that will be adopted in tackling them
- a discussion of the scientific method and its relation to evidence. In
particular it makes an important distinction between how science works in the
case of the experimental sciences on the one hand, and the
historical/geographical sciences on the other.
PART II (Chapters 3 to 6) presents the present scientific understanding of the
Universe. The scientific method has led to a tremendous growth in knowledge of
the way matter is organised and functions. The chapters in this part give a
brief outline of some of the most important of these discoveries. Chapter 3
focuses on the underlying fundamental laws, covering concepts from physics and
chemistry. It then comments on how these laws underlie the nature of the
physical world (minerals, rocks, mountains, the Earth). Chapter 4 focuses on the
functioning of complex systems, covering the range of biological sciences, and
proposing a set of basic principles that underlie the functioning of truly
complex systems such as life. Chapter 5 focuses on the environment within which
all this takes place (the Universe around us), covering astronomy and cosmology.
However this cosmological understanding is uncertain in some aspects, and
limited in others; Chapter 6 discusses some of these uncertainties and
limitations, ultimately founded in the uniqueness of the universe.
PART III (Chapters 7 and 8) turns to the theme of humanity and the Universe.
Chapter 7 introduces the Anthropic question, i.e. the puzzling fact that the
physical Universe seems fine-tuned to permit the existence of complex physical
organisms, including human life. A purely scientific approach to understanding
this feature is found to be inconclusive. This discussion provides the
scientific basis for whatever approach one chooses to take towards the `big
questions' mentioned in Chapter 1. Finally the limits of science are discussed
in Chapter 8. There are important aspects of human existence that will forever
remain beyond its domain. That statement does not of course in any way undermine
its magnificent achievements within its proper domain, which is presented in the
rest of this text.
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