

According to many physicists, the primary goal of physics today is the grand unified theory. it is supposed to describe the four forces as different aspects of a same force.

the four forces, gravity, electromagnetic force, strong nuclear force, weak nuclear force have to be established as single form at some point(energy level) that get branched later on in the evolution process(cooling of earth) after big bang

scientists,indeed,successfully combined three of the forces other than gravity.the first two forces that got unified were electromagnetic force and weak nuclear force in the year 1967 by Abdus Salam and Steven Weinberg.



They suggested that there were other massive particles along with photon(EM force carrier) having same spin,that carry weak nuclear force, collectively called as massive vector bosons(W+,W-,Z0), and the way they got divided is explained by a property called spontaneous symmetry breaking,which means that,what ever appear to be a number of completely different particles at low energies are in fact found to be all the same type of particle,only in different states.all these particles behaves similarly at higher energies(around 100's of Gev) and the symmetry get broken at lower particle energies to form massive W+,W- and Z0 along with photons.



later it was found that the strong nuclear force which was carried by gluons get weaker at higher energies making quarks and gluons act freely.

It creates a new hope,that there must be some energy level where gluons, photons and bosons all behave the same & they predicted that it must be around thousand million million Gev and it can't be proved as there are no such oscillators till date.

they also predicted that quarks and electrons would behave the same at that grand unified energy level.



Now the process of unifying gravity along with the other three is going on...



hope they will find answers soon.

check this video

