In cosmology, the Steady State theory is a
now-obsolete theory and model alternative
to the Big Bang theory of the universe's origin.
In steady state views, new matter is continuously
created as the universe expands, thus adhering
to the perfect cosmological principle.
While the steady state model enjoyed some
popularity in the first half of the 20th century,
it is now rejected by the vast majority of
professional cosmologists and other scientists,
as the observational evidence points to a
Big Bang-type cosmology and a finite age of
the universe.
History
Sir James Jeans, in the 1920s, was the first
to conjecture a steady state cosmology based
on a hypothesized continuous creation of matter
in the universe. The idea was then revised
in 1948 by Fred Hoyle, Thomas Gold, Hermann
Bondi and others. The steady state theory
of Bondi and Gold was inspired by the circular
plot of the film Dead of Night, which they
had watched together. Theoretical calculations
showed that a static universe was impossible
under general relativity, and observations
by Edwin Hubble had shown that the universe
was expanding. The steady state theory asserts
that although the universe is expanding, it
nevertheless does not change its appearance
over time; the universe has no beginning and
no end.
Problems with the steady-state theory began
to emerge in the late 1960s, when observations
apparently supported the idea that the universe
was in fact changing: quasars and radio galaxies
were found only at large distances, not in
closer galaxies. Whereas the Big Bang theory
predicted as much, the Steady State theory
predicted that such objects would be found
throughout the universe, including close to
our own galaxy.
For most cosmologists, the refutation of the
steady-state theory came with the discovery
of the cosmic microwave background radiation
in 1965, which was predicted by the Big Bang
theory. Stephen Hawking described this discovery
as "the final nail in the coffin of the steady-state
theory". The steady-state theory explained
microwave background radiation as the result
of light from ancient stars that has been
scattered by galactic dust. However, the cosmic
microwave background level is very even in
all directions, making it difficult to explain
how it could be generated by numerous point
sources and the microwave background radiation
shows no evidence of characteristics such
as polarization that normally associated with
scattering. Furthermore, its spectrum is so
close to that of an ideal black body that
it could hardly be formed by the superposition
of contributions from a multitude of dust
clumps at different temperatures as well as
at different redshifts. Steven Weinberg wrote
in 1972,
The steady state model does not appear to
agree with the observed dL versus z relation
or with source counts ... In a sense, the
disagreement is a credit to the model; alone
among all cosmologies, the steady-state model
makes such definite predictions that it can
be disproved even with the limited observational
evidence at our disposal. The steady-state
model is so attractive that many of its adherents
still retain hope that the evidence against
it will disappear as observations improve.
However, if the cosmic microwave background
radiation ... is really black-body radiation,
it will be difficult to doubt that the universe
has evolved from a hotter, denser early stage.
Since this discovery, the Big Bang theory
has been considered to provide the best explanation
of the origin of the universe. In most astrophysical
publications, the Big Bang is implicitly accepted
and is used as the basis of more complete
theories.
Quasi-steady state
Quasi-steady state cosmology was proposed
in 1993 by Fred Hoyle, Geoffrey Burbidge,
and Jayant V. Narlikar as a new incarnation
of the steady state ideas meant to explain
additional features unaccounted for in the
initial proposal. The theory suggests pockets
of creation occurring over time within the
universe, sometimes referred to as minibangs,
mini-creation events, or little bangs. After
the observation of an accelerating universe,
further modifications of the model were made.
Other proponents
Chaotic Inflation theory has many similarities
with steady state theory, however on a much
larger scale than originally envisaged. It
is the C-field and the notion of quasi-steady
state universe that has some resemblance to
chaotic inflation theory or eternal inflation,
which sometimes posits an infinite universe
with neither beginning nor end, in which inflation
operates continuously, on a scale beyond the
observable universe, to create the matter
of the cosmos. However, both steady state
and quasi-steady state assert that the creation
events of the universe can be observed within
the observable universe, whereas inflationary
theories do not posit inflation as an ongoing
process within the observable universe.
Criticism
Astrophysicist and cosmologist Ned Wright
has pointed out flaws in the theory. These
first comments were soon rebutted by the proponents.
Wright and other mainstream cosmologists reviewing
QSS have pointed out new flaws and discrepancies
with observations left unexplained by proponents.
See also
Conservation of angular momentum
External articles and references
Criticism
Wright, E. L.. "Errors in the Steady State
and Quasi-SS Models". UCLA, Physics & Astronomy
Department. 
Assis, A. K. T.; Neves, M. C. D.. "History
of 2.7 K Temperature Prior to Penzias and
Wilson". Apeiron 2: 79–87. 
References
Hoyle, F.; Burbidge, G.; Narlikar, J. V..
"A quasi-steady state cosmological model with
creation of matter". The Astrophysical Journal
410: 437–457. Bibcode:1993ApJ...410..437H.
doi:10.1086/172761. 
Hoyle, F.; Burbidge, G.; Narlikar, J. V..
"Astrophysical deductions from the quasi-steady
state cosmology". Monthly Notices of the Royal
Astronomical Society 267: 1007–1019. Bibcode:1994MNRAS.267.1007H. 
Hoyle, F.; Burbidge, G.; Narlikar, J. V..
"Astrophysical deductions from the quasi-steady
state : Erratum". Monthly Notices of the
Royal Astronomical Society 269: 1152. Bibcode:1994MNRAS.269.1152H. 
Hoyle, F.; Burbidge, G.; Narlikar, J. V..
"Further astrophysical quantities expected
in a quasi-steady state Universe". Astronomy
and Astrophysics 289: 729–739. Bibcode:1994A&A...289..729H. 
Hoyle, F.; Burbidge, G.; Narlikar, J. V..
"The basic theory underlying the quasi-steady
state cosmological model". Proceedings of
the Royal Society 
A 448: 191. Bibcode:1995RSPSA.448..191H. doi:10.1098/rspa.1995.0012. 
Notes and citations
Further reading
Farmer, B. L.. Universe Alternatives: Emerging
Concepts of Size, Age, Structure, and Behavior.
Gilliland Printing. ISBN 0-9649983-4-3. 
Hoyle, F.; Burbidge, G.; Narlikar, J. V..
A Different Approach to Cosmology. Cambridge
University Press. ISBN 0-521-66223-0. 
Mitton, S.. Conflict in the Cosmos: Fred Hoyle's
Life in Science. Joseph Henry Press. ISBN 0-309-09313-9. 
Mitton, S.. Fred Hoyle: A Life in Science.
Aurum Press. ISBN 1-85410-961-8. 
