Big Bang


Big Bang Essay, Research Paper

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.


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