Claim CE420:
The theory of a big bang has been shaken with unresolvable
inconsistencies, such as an unexpectedly uneven distribution of matter in
the universe and a need for dark matter. Several astronomers think it is
no longer a valid theory.
Source:
Response:
- The big bang is supported by a great deal of evidence:
- Einstein's general theory of relativity implies that the universe
cannot be static; it must be either expanding or contracting.
- The more distant a galaxy is, the faster it is receding from us (the
Hubble law). This indicates that the universe is expanding. An
expanding universe implies that the universe was small and compact
in the distant past.
- The big bang model predicts that cosmic microwave background (CMB)
radiation should appear in all directions, with a blackbody spectrum
and temperature about 3 degrees K. We observe an exact blackbody
spectrum with a temperature of 2.73 degrees K.
- The CMB is even to about one part in 100,000. There should be a
slight unevenness to account for the uneven distribution of matter
in the universe today. Such unevenness is observed, and at a
predicted amount.
- The big bang predicts the observed abundances of primordial
hydrogen, deuterium, helium, and lithium. No other models have been
able to do so.
- The big bang predicts that the universe changes through time.
Because the speed of light is finite, looking at large distances
allows us to look into the past. We see, among other changes, that
quasars were more common and stars were bluer when the universe was
younger.
Note that most of these points are not simply observations that fit
with the theory; the big bang theory predicted them.
- Inconsistencies are not necessarily unresolvable. The clumpiness of
the universe, for example, was resolved by finding unevenness in the
CMB. Dark matter has been observed in the effects it has on star and
galaxy motions; we simply do not know what it is yet.
There are still unresolved observations. For example, we do not
understand why the expansion of the universe seems to be speeding up.
However, the big bang has enough supporting evidence behind it that it
is likely that new discoveries will add to it, not overthrow it.
For example, inflationary universe theory proposes that the size of the
universe increased exponentially when the universe was a fraction of a
second old (Guth 1997). It was proposed to explain why the big bang
did not create large numbers of magnetic monopoles. It also
accounts for the observed flatness of space, and it predicted
quantitatively the pattern of unevenness of the CMB. Inflationary
theory is a significant addition to big bang theory, but it is an
extension of big bang theory, not a replacement.
Links:
Feuerbacher, Björn and Ryan Scranton. 2006. Evidence for the Big
Bang. http://www.talkorigins.org/faqs/astronomy/bigbang.html
References:
- Guth, Alan H., 1997. (see below).
Further Reading:
Ferris, Timothy. 1997. The Whole Shebang. New York: Simon &
Schuster.
Guth, Alan H. 1997. The Inflationary Universe. Reading, MA:
Addison-Wesley.
Harrison, E. R. 2000. Cosmology: The science of the
universe. Cambridge University Press.
created 2004-4-21, modified 2006-1-26