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Big Bang Effect
It is always a mystery about how the universe began,
whether if and when it will end. Astronomers construct hypotheses called
cosmological models that try to find the answer. There are two types of models:
Big Bang and Steady State. However, through many observational evidences, the
Big Bang theory can best explain the creation of the universe.
The Big
Bang model postulates that about 15 to 20 billion years ago, the universe
violently exploded into being, in an event called the Big Bang. Before the Big
Bang, all of the matter and radiation of our present universe were packed
together in the primeval fireball—an extremely hot dense state from which the
universe rapidly expanded.1 The Big Bang was the start of time and space. The
matter and radiation of that early stage rapidly expanded and cooled. Several
million years later, it condensed into galaxies. The universe has continued to
expand, and the galaxies have continued moving away from each other ever since.
Today the universe is still expanding, as astronomers have observed.
The
Steady State model says that the universe does not evolve or change in time.
There was no beginning in the past, nor will there be change in the future. This
model assumes the perfect cosmological principle. This principle says that the
universe is the same everywhere on the large scale, at all times.2 It maintains
the same average density of matter forever.
There are observational
evidences found that can prove the Big Bang model is more reasonable than the
Steady State model. First, the redshifts of distant galaxies. Redshift is a
Doppler effect which states that if a galaxy is moving away, the spectral line
of that galaxy observed will have a shift to the red end. The faster the galaxy
moves, the more shift it has. If the galaxy is moving closer, the spectral line
will show a blue shift. If the galaxy is not moving, there is no shift at all.
However, as astronomers observed, the more distance a galaxy is located from
Earth, the more redshift it shows on the spectrum. This means the further a
galaxy is, the faster it moves. Therefore, the universe is expanding, and the
Big Bang model seems more reasonable than the Steady State model.
The
second observational evidence is the radiation produced by the Big Bang. The Big
Bang model predicts that the universe should still be filled with a small
remnant of radiation left over from the original violent explosion of the
primeval fireball in the past. The primeval fireball would have sent strong
shortwave radiation in all directions into space. In time, that radiation would
spread out, cool, and fill the expanding universe uniformly. By now it would
strike Earth as microwave radiation. In 1965 physicists Arno Penzias and Robert
Wilson detected microwave radiation coming equally from all directions in the
sky, day and night, all year.3 And so it appears that astronomers have detected
the fireball radiation that was produced by the Big Bang. This casts serious
doubt on the Steady State model. The Steady State could not explain the
existence of this radiation, so the model cannot best explain the beginning of
the universe.
Since the Big Bang model is the better model, the
existence and the future of the universe can also be explained. Around 15 to 20
billion years ago, time began. The points that were to become the universe
exploded in the primeval fireball called the Big Bang. The exact nature of this
explosion may never be known.
However, recent theoretical breakthroughs,
based on the
principles of quantum theory, have suggested that space,
and the
matter within it, masks an infinitesimal realm of utter chaos,
where events happen randomly, in a state called quantum
weirdness.4
Before the universe began, this chaos was all there
was. At some time, a portion of this randomness happened to form a bubble, with
a temperature in excess of 10 to the power of 34 degrees Kelvin. Being that hot,
naturally it expanded. For an extremely brief and short period, billionths of
billionths of a second, it inflated. At the end of the period of inflation, the
universe may have a diameter of a few centimetres. The temperature had cooled
enough for particles of matter and antimatter to form, and they instantly
destroy each other, producing fire and a thin haze of matter-apparently because
slightly more matter than antimatter was formed.5 The fireball, and the smoke of
its burning, was the universe at an age of trillionth of a second.
The
temperature of the expanding fireball dropped rapidly, cooling to a few billion
degrees in few minutes. Matter continued to condense out of energy, first
protons and neutrons, then electrons, and finally neutrinos. After about an
hour, the temperature had dropped below a billion degrees, and protons and
neutrons combined and formed hydrogen, deuterium, helium. In a billion years,
this cloud of energy, atoms, and neutrinos had cooled enough for galaxies to
form. The expanding cloud cooled still further until today, its temperature is a
couple of degrees above absolute zero.
In the future, the universe may
end up in two possible situations. From the initial Big Bang, the universe
attained a speed of expansion. If that speed is greater than the universe’s own
escape velocity, then the universe will not stop its expansion. Such a universe
is said to be open. If the velocity of expansion is slower than the escape
velocity, the universe will eventually reach the limit of its outward thrust,
just like a ball thrown in the air comes to the top of its arc, slows, stops,
and starts to fall. The crash of the long fall may be the Big Bang to the
beginning of another universe, as the fireball formed at the end of the
contraction leaps outward in another great expansion.6 Such a universe is said
to be closed, and pulsating.
If the universe has achieved escape
velocity, it will continue to expand forever. The stars will redden and die, the
universe will be like a limitless empty haze, expanding infinitely into the
darkness. This space will become even emptier, as the fundamental particles of
matter age, and decay through time. As the years stretch on into infinity,
nothing will remain. A few primitive atoms such as positrons and electrons will
be orbiting each other at distances of hundreds of astronomical units.7 These
particles will spiral slowly toward each other until touching, and they will
vanish in the last flash of light. After all, the Big Bang model is only an
assumption. No one knows for sure that exactly how the universe began and how it
will end. However, the Big Bang model is the most logical and reasonable theory
to explain the universe in modern science.
ENDNOTES
1.
Dinah L. Mache, Astronomy, New York: John Wiley & Sons,
Inc., 1987.
p. 128.
2. Ibid., p. 130.
3. Joseph Silk, The Big Bang, New
York: W.H. Freeman and
Company, 1989. p. 60.
4. Terry Holt, The
Universe Next Door, New York: Charles
Scribner’s Sons, 1985. p. 326.
5. Ibid., p. 327.
6. Charles J. Caes, Cosmology, The Search For
The Order Of
The Universe, USA: Tab Books Inc., 1986. p. 72.
7.
John Gribbin, In Search Of The Big Bang, New York: Bantam
Books, 1986.
p. 273.
BIBLIOGRAPHY
Boslough, John. Stephen Hawking’s
Universe. New York: Cambridge
University Press, 1980.
Caes, J.
Charles. Cosmology, The Search For The Order Of The
Universe. USA: Tab
Books Inc., 1986.
Gribbin, John. In Search Of The Big Bang. New York:
Bantam
Books, 1986.
Holt, Terry. The Universe Next Door. New
York: Charles
Scribner’s Sons, 1985.
Kaufmann, J. William III.
Astronomy: The Structure Of The
Universe. New York: Macmillan Publishing
Co., Inc., 1977.
Mache, L. Dinah. Astronomy. New York: John Wiley &
Sons, Inc.,
1987.
Silk, Joseph. The Big Bang. New York: W.H.
Freeman and Company,
1989.