Cosmology, is the study of the origin, evolution,
and eventual fate of the universe.
Physical cosmology is the scholarly and scientific
study of the origin, evolution, large-scale
structures and dynamics, and ultimate fate
of the universe, as well as the scientific
laws that govern these realities.
Religious cosmology is a body of beliefs based
on the historical, mythological, religious,
and esoteric literature and traditions of
creation and eschatology.
Physical cosmology is studied by scientists,
such as astronomers, and theoretical physicists;
and academic philosophers, such as metaphysicians,
philosophers of physics, and philosophers
of space and time.
Modern cosmology is dominated by the Big Bang
theory, which attempts to bring together observational
astronomy and particle physics.
Although the word cosmology is recent, the
study of the universe has a long history involving
science, philosophy, esotericism and religion.
Related studies include cosmogony, which focuses
on the origin of the Universe, and cosmography,
which maps the features of the Universe.
Cosmology is also connected to astronomy,
but while the former is concerned with the
Universe as a whole, the latter deals with
individual celestial objects.
Disciplines
Physics and astrophysics have played a central
role in shaping the understanding of the universe
through scientific observation and experiment.
What is known as physical cosmology has been
shaped through both mathematics and observation
in an analysis of the whole universe.
The universe is generally understood to have
begun with the Big Bang, followed almost instantaneously
by cosmic inflation; an expansion of space
from which the universe is thought to have
emerged 13.798 ± 0.037 billion years ago.
Metaphysical cosmology has also been described
as the placing of man in the universe in relationship
to all other entities.
This is exemplified by the observation made
by Marcus Aurelius of a man's place in that
relationship: "He who does not know what the
world is does not know where he is, and he
who does not know for what purpose the world
exists, does not know who he is, nor what
the world is."
Physical cosmology
Physical cosmology is the branch of physics
and astrophysics that deals with the study
of the physical origins and evolution of the
Universe.
It also includes the study of the nature of
the Universe on its very largest scales.
In its earliest form it was what is now known
as celestial mechanics, the study of the heavens.
The Greek philosophers Aristarchus of Samos,
Aristotle and Ptolemy proposed different cosmological
theories.
In particular, the geocentric Ptolemaic system
was the accepted theory to explain the motion
of the heavens until Nicolaus Copernicus,
and subsequently Johannes Kepler and Galileo
Galilei proposed a heliocentric system in
the 16th century.
This is known as one of the most famous examples
of epistemological rupture in physical cosmology.
With Isaac Newton and the 1687 publication
of Principia Mathematica, the problem of the
motion of the heavens was finally solved.
Newton provided a physical mechanism for Kepler's
laws and his law of universal gravitation
allowed the anomalies in previous systems,
caused by gravitational interaction between
the planets, to be resolved.
A fundamental difference between Newton's
cosmology and those preceding it was the Copernican
principle that the bodies on earth obey the
same physical laws as all the celestial bodies.
This was a crucial philosophical advance in
physical cosmology.
Modern scientific cosmology is usually considered
to have begun in 1917 with Albert Einstein's
publication of his final modification of general
relativity in the paper "Cosmological Considerations
of the General Theory of Relativity".
General relativity prompted cosmogonists such
as Willem de Sitter, Karl Schwarzschild and
Arthur Eddington to explore the astronomical
consequences of the theory, which enhanced
the growing ability of astronomers to study
very distant objects.
Prior to this, physicists assumed that the
Universe was static and unchanging.
In parallel to this dynamic approach to cosmology,
one long-standing debate about the structure
of the cosmos was coming to a climax.
Mount Wilson astronomer Harlow Shapley championed
the model of a cosmos made up of the Milky
Way star system only; while Heber D. Curtis
argued for the idea that spiral nebulae were
star systems in their own right – island
universes.
This difference of ideas came to a climax
with the organization of the Great Debate
at the meeting of the National Academy of
Sciences in Washington on 26 April 1920.
The resolution of this debate came with the
detection of novae in the Andromeda galaxy
by Edwin Hubble in 1923 and 1924.
Their distance established spiral nebulae
well beyond the edge of the Milky Way.
Subsequent modelling of the universe explored
the possibility that the cosmological constant,
introduced by Einstein in his 1917 paper,
may result in an expanding universe, depending
on its value.
Thus the Big Bang model was proposed by the
Belgian priest Georges Lemaître in 1927 which
was subsequently corroborated by Edwin Hubble's
discovery of the red shift in 1929 and later
by the discovery of the cosmic microwave background
radiation by Arno Penzias and Robert Woodrow
Wilson in 1964.
These findings were a first step to rule out
some of many alternative physical cosmologies.
Recent observations made by the COBE and WMAP
satellites observing this background radiation
have effectively, in many scientists' eyes,
transformed cosmology from a highly speculative
science into a predictive science, as these
observations matched predictions made by a
theory called Cosmic inflation, which is a
modification of the standard Big Bang model.
This has led many to refer to modern times
as the "Golden age of cosmology".
On 17 March 2014, astronomers at the Harvard-Smithsonian
Center for Astrophysics announced the detection
of gravitational waves, providing strong evidence
for inflation and the Big Bang.
However, on 19 June 2014, lowered confidence
in confirming the cosmic inflation findings
was reported.
Historical cosmologies
Table notes: the term "static" simply means
not expanding and not contracting.
Symbol G represents Newton's gravitational
constant; Λ is the cosmological constant.
Religious and mythological cosmology
Mythological cosmology deals with the world
as the totality of space, time and all phenomena.
Historically, it has had quite a broad scope,
and in many cases was founded in religion.
The ancient Greeks did not draw a distinction
between this use and their model for the cosmos.
However, in modern use it addresses questions
about the Universe which are beyond the scope
of science.
It is distinguished from religious cosmology
in that it approaches these questions using
philosophical methods.
Modern metaphysical cosmology tries to address
questions such as:
What is the origin of the Universe?
What is its first cause?
Is its existence necessary?
What are the ultimate material components
of the Universe?
What is the ultimate reason for the existence
of the Universe?
Does the cosmos have a purpose?
Does the existence of consciousness have a
purpose?
How do we know what we know about the totality
of the cosmos?
Does cosmological reasoning reveal metaphysical
truths?
See also
Notes
References
Cronin, Vincent, The View from Planet Earth:
Man Looks at the Cosmos, New York: William
Morrow & Company, Inc., 1981, ISBN 0-688-00642-6
Jean-Marc Rouvière, Brèves méditations
sur la création du monde, L'Harmattan, Paris
2006.
Roos, Matts Introduction to Cosmology.
John Wiley & Sons, Ltd, Chichester: 2003.
Hawley, John F. & Katerine A. Holcomb Foundations
of Modern Cosmology.
Oxford University Press, Oxford: 1998.
Hetherington, Norriss S. Cosmology: Historical,
Literary, Philosophical, Religious, and Scientific
Perspectives.
Garland Publishing, New York: 1993.
Long, Barry.
The Origins of Man and the Universe ISBN 0-9508050-6-8
Martinus Thomsen's The Third Testament is
about the explanation of life, everything
inside it and the reason of it.
Arthur Koestler's The Sleepwalkers provides
a scholarly study of the history of cosmology
from the Chaldeans to Kepler.
Schechner, Sara J. Comets, Popular Culture,
and the Birth of Modern Cosmology.
Princeton, New Jersey: Princeton University
Press.
1997.
Weinberg, Steven, 1992.
Dreams of a Final Theory ISBN 0-679-41923-3
– non-technical book.
Weinberg, Steven, 2008, Cosmology ISBN 0-19-852682-2
– theoretical textbook.
External links
Cosmic Journey: A History of Scientific Cosmology
from the American Institute of Physics
Project Cosmology A schematic for the cosmos
Introduction to Cosmology David Lyth's lectures
from the ICTP Summer School in High Energy
Physics and Cosmology
The Sophia Centre The Sophia Centre for the
Study of Cosmology in Culture, University
of Wales Trinity Saint David
the Genesis cosmic chemistry module
