Wednesday, July 14, 2010

STRING THEORY



STRING THEORY

What is the basic need of string theory?

Physicists all around the world have been searching from the mid twentieth century for a theory which unifies all the four fundamental forces in nature -the strong nuclear force,the weak nuclear force,the electromagnetic force and the gravitational force.They were somewhat successful in unifying these theories giving equations and hypothesizing that, if we go back in time when the universe originated we could see that the nuclear the strong and the weak and the electromagnetic force can all be bonded into one.This was further proved by quantum mechanics in proper particle terms. But the main force was missing, the force experienced most, in our lives- GRAVITY.

So the string theory came into existence again as an attempt to unify the forces after being dead for a long time.

what is string theory??
It states that if we go into electrons and quarks in an atom,there are smaller objects ( about 1 billion times smaller than the atoms!) which are string like and can vibrate giving the particles the mass,spin etc.
It is what is said to give the binding power between the electrons and the protons in an atom.these strings are mass less!!! and are associated with gravity! and were called gravitons.String theory predicts that this gravitons are the cause of gravity,and it is this what makes up the building block of everything.The theory also states extra dimensions i.e more than what we know which are three dimensions of space and one of time..

History
In 1965 Gabriel Veneziano discovered a 200 year old equation,which shows the strong force between atoms originally discovered by a Swiss mathematician-Oeler,he quickly became popular for that discovery afterwards...
As time passed Oelers equation was passed into an American physicist Lenard Cuskin who
stated that Oelers formula exactly agreed with a particle which was like a string and could vibrate.But Cuskins theory was not accepted by the scientific world so it appeared string theory was dead.
Scientists then made a strange theory that all forces can be explained in terms of particles for eg: more the particle like photon is exchanged between the atoms more the force.
And they were somewhat successful stating that if we go back to the time just after the big bang all the three forces the strong and weak nuclear force and the electromagnetic force could be one grand force.But where was gravity?
In 1973 John Schwartz stated the equations were displaying gravity and that gravitons a small particle about a billion times smaller than the atoms which were mass less was giving gravity to objects. Mass less and gravity!!!But then again there was no response..

So he was joined by Michael Greene in his venture,the task was incredibly tough since it had a lot of mathematical anomalies the whole world was looked in terms of strings that vibrate!!!but after years of work they were able to solve the anomalies and when they calculated these equations,they ended up with the same result on both the sides.

1,2,3,4,5,6 how many??
String theorists predict that there are not just the three dimensions of space and one of time,but there are extra 6 dimensions of space which are so billion times smaller than the atoms that look like curved objects!!! but again after this theory Witten a world famous physicist considered even as the predecessor to Einstein proposed one more dimension making the dimensions to a mindblowing 11 !!
There were actually five string theories produced at first,but Witten concluded in 1995 that these are five different ways of looking at the same theory. The string theory was concluded into one and was called the M theory..
and nobody really knows what the M stands for,so mystical just like the whole theory itself..

REFERENCES:
www.youtube.com
NOTE: This assignment has been done by a person(me) who knows very little about string theory.So mistakes might have have crept in.I regret any mistake.
by:
Vysakhan.H

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