Big Bang Theory Essay, Research Paper

?The more I see, the more I see there is to see?

John Sebastian

For a few centuries scientists are discovering and implementing

astronomical definitions and rules of the modern physics. The more they

learnt , the more their attention was turning to the global question of

starting point of universe, history.

In search for solution philosophers speculated about the cause of

massive explosion and whether anything existed before the ?Big Bang?.

Scientists studied different theories, observations and have been making

their conclusions based on it. It led them further to discovering

general laws of physics and write the image of the early Universe.

Yet there is no scientific evidence neither in regard to

Cause of the big bang, nor its pre-history.

the question is still waiting to be answered:

What was the beginning of the beginning?

Till 20th century It was almost impossible to suggest science can

explain the origin of the Universe. Today there is overwhelming evidence

that it began in a hot, dense state around 13-15 billion years ago.

Big Bang theory is based on general relativity ( discovered by Albert

Einstein in 1915, although he initially believed in static universe ). It

started with outlining major features of an explosive event such as

temperature ( which indicated size and age of the Universe ), particles?

interaction and expansion of matter.

Unfortunately, scientists are limited in how far they can go with

physical insight of Big Bang events. The limit is first 10 (-43) seconds.

The big bang model: ( according to Stephen hawking )

?massive explosion (T: over 10 billion degrees)

10(-43) seconds (t: 10(32) degrees):grand Unification era ( unifies strong,

weak and electromagnetic forces )

10(-34) seconds: (t: 10(27) degrees):quarks and anti-quarks domination

era

10(-10) seconds: (t: 10(15) degrees): quark era; cool enough for

protons, neutrons to form; electroweak force splits into

the weak force and electromagnetism.

1 second: (t: 10(10) degrees): nucleosynthesis era; neutron and proton

bind together and result in nuclei of hydrogen, helium, deuterium,

beryllium and lithium.

3 minutes: (t: 10(9) degrees): matter era; matter and radiation couple

together; electrons and nuclei cannot resist electromagnetic force

and combine to form atoms; formation of atoms; nuclei had interacted

with the radiation;

300000 years: (t: 3000 degrees): matter and radiation effectively

decouple; naked electric charge disappear; however most of the

radiation remained undisturbed as universe expanded;

1000 million years: (t: 3000 degrees ? stable): formation of stars,

quasars and galaxies.

15.000 million years: (t: 3 degrees k ): Solar system condense around

stars; formation of planets; atoms form molecules and living matter.

Georges Lemaitre (Belgian cosmologist ) conventionally called Big

Bang ?cosmic egg explosion?. He suggested that ?egg? contained all the

empty space and all the matter in the Universe that exists now and

expanded outwards from a singularity.

non-static models of the Universe were developed earlier by Einstein in

1917 and by Alexander Friedmann in 1922. They have discovered that the

major part of the Universe is not balanced: it either expands or

tightens. According to Friedmann?s model all galaxies are moving away

from each other which, not surprisingly, suggests that the whole

Universe must have had a definite beginning of time.

the steady state model of the Universe ( suggested in 1940 ) denied the

fact that Universe could be created ?out of nothing? in one moment.

However, using radio and optical telescopes modern scientists

produced enough evidence that Universe expanding and cooling as

time passes by. Therefore, it is expanding.

Starting in 1920s scientists studied different galaxies and stars. They

discovered that stars from other galaxies are missing same colours as

stars in our galaxy. Though they were shifted

by the same relative amount towards the red colour. Wavelengths of

light of the star are very small. Longest wavelengths appear at the red

end of the spectrum ( object moving away from us), shortest ones are at

the blue end( object moving towards us): discovered by Christian

Doppler ( discovery is called ?Doppler effect? in his honour ).

It has also been discovered that the amount of the shift depends on the

speed with which a star is approaching or receding from us. In 1924

Edwin Hubble discovered that, in fact, most galaxies are moving away

from our galaxy and the farther the galaxy the faster it is moving away.

It suggests that before at definite moment of time all galaxies would

be squashed together in smaller, dense state that once has been equal

zero. The relationship between red shift ( and velocity) and distance of a

galaxy/star is called Hubble?s Law: as distance increases, velocity also

increases. The Universe cannot stand still. Gravity would bring all

galaxies together if they were not moving away from each other.

?The Universe is not expanding into anything. It is everything there is.?

John D. Barrow

As mentioned before, when matter and radiation stopped interacting

with one each other, some amount of radiation remained undisturbed.

It was confirmed in 1940 by George Gamow, R. Alpher and R. Herman.

They indicated that universe was very hot at the Big Bang, since elements

heavier than hydrogen can be formed only at high temperature.

Cosmic background radiation, predicted by Alpher and Herman was

Accidentally detected by Arno Penzias and Robert Wilson in 1965 while

Testing new radio telescope. Later, in the late 1980s Cosmic

Background Explorer satellite was launched which detected very

slight variations in the intensity of the microwave background;

established beyond doubts that cosmic background radiation

discovered by scientists is electromagnetic radiation with t close to

2.7K, – temperature required by Big Bang model. Once again, it proves the

inflationary model of the Big Bang.