Everything that exist, or have ever existed is glued and made from only 4 types of interaction, the 4 Fundamental forces of nature. From stars to atomic nuclei, galaxies to your toys , ruthless blackholes to each kind heart , everything is held together by these 4 forces. These are  

  • Gravity.  
  • The weak force.  
  • Electromagnetism.  
  • The strong force. 

They are fundamental forces and govern everything in the universe and are thus the basis of everything and the core of science.  


Gravitational force is the weakest of all four fundamental forces . But it has the longest range (range is virtually infinite) and every particle having mass and energy experience this force. It is about Its 6 thousand trillion trillion trillion (6*10^39) times weaker than the strong force. But it holds stars, planets galaxies in orbit.  Gravity is always attractive and never repulsive. The formula for calculation Gravity was given by Isaac Newton: 

F = G(m1m2)/R2

It is directly proportional to the product of masses of two bodies and inversely proportional to the square of distance between them.  

The mechanism of gravity is however best explained by the General relativity Theory of Albert Einstein. Which explains gravity not as a force, but rather as a curvature of spacetime. Just like a heavy ball attached to a rubber sheet, deforms it. Similarly, every large object deforms the geometry of spacetime causing gravity. 

It is the only force which is not proven to be transferred by a particle. The Quantum Gravity theory has theorised a particle named Graviton, as a carrier of gravity. But this hypothesis is not yet confirmed by any experimental evidence. 


The weak force or electroweak interaction is responsible for the decay of atomic nuclei. So it is basis of all Fission and Fusion reactions that keep the stars burning and thus supporting life. It has the shortest range of 10-18m, which is 0.1% of the diameter of a proton.  The Quantum mechanics explained this force as an exchange of W and Z bosons between particles (fermions) . 

Weak force has been unified with electromagnetic forces above the unification energy. Although these two forces appear very different at everyday low energies, the theory models them as two different aspects of the same force. Above the unification energy, on the order of 246 GeV,[a] they would merge into a single force.   This is the Unification theory.  


This is the second strongest force after the strong force and it acts on electrically charged particles. It has strength of 1/137 relative to the strong force but has an infinite range. The magnitude of this force is given by coulomb’s law: 

F = k • Q1 • Q2 / d2  

The greater the charge, the stronger will be the force. 

Electrical and magnetic phenomena have been observed since ancient times, but it was only in the 19th century James Clerk Maxwell discovered that electricity and magnetism are two aspects of the same fundamental interaction. By 1864, Maxwell’s equations had rigorously quantified this unified interaction.  

The mechanism is best explained by Quantum electrodynamics (QED), according to the theory Electromagnetic forces are transferred between charged particles through the exchange of massless, force-carrying bosons called photons, which are also the particle components of light.   

All atoms, molecules, compounds and chemical reactions are based on electromagnetic force. Friction, elasticity , normal force and many other phenomena are direct consequence of this force. So ironically, it is light (photons) that glue all the atoms together. 


This force holds the nucleus of an atom together. It is the strongest of the fundamental forces, but it is very short ranged. It acts over a range of about 10-15m, which is the average diameter of a medium sized nucleus. This force is attractive. It’s 6 thousand trillion trillion trillion (that’s 39 zeroes after 6!) times stronger than the force of gravity. This force overcome the electrostatic repulsion force between the subatomic particles in the nucleus and hold the atom together. 

The mechanism of strong force is given by Quantum Chromodynamic theory (QCD). Gluons are the force carrier of the theory, like photons are for the electromagnetic force in quantum electrodynamics. These gluons are exchanged between Quarks (there are 6 types of quarks that make up hadrons such as protons, neutrons and pions . ) The strong force is odd, though, because unlike any of the other fundamental forces, it gets weaker as subatomic particles move closer together. It actually reaches maximum strength when the particles are farthest away from each other. Once within range, massless charged bosons called gluons transmit the strong force between quarks and keep them “glued” together. 


These 4 fundamental forces are the epicenter of literally everything. Many believe that one day all 4 forces will be unified to produce Theory of Everything, the ultimate ambition and eternal bliss of theoretical physics. Electromagnetic and weak forces have already been unified in electroweak force. Unifying strong force with electroweak force will result in electronuclear force (Grand Unified Theory) . And finally, by one day, we hope to unite gravity with the rest to produce a force, that can possibly explain the entire universe.