Four Fundamental Forces of the Universe

 Four Fundamental Forces of the Universe

 

If you are interested in science and want to know what forces govern the universe then you are in the right place. This blog will explain the fundamental forces simply and hopefully, it may come in handy to you (if not now, then in the future).

 

Gravity

Sounds familiar, right? If you don’t know what gravity is, just give up on your dream of becoming a scientist (kidding). Don’t forget what I tell you; gravity is the simplest force. It was discovered by Sir Isaac Newton, and it explains why you cannot get up from bed early in the morning, means it explains why the Earth attracts objects towards it, not just Earth but any planet or star or even a galaxy you can think of attracts everything towards it. Even the device you are holding right now is attracting you. But why don’t you get any closer to it even though it is attracting you? That’s because its gravity is not enough to make you move. It may not attract you towards it, but it still has gravity because it has mass and occupies space. Confused? Alright, here’s a simple explanation: The more mass an object has, the more gravity it exerts. That is why Earth’s gravity is stronger than the device you’re holding, because of its mass.

Gravity is the reason you are sticked to Earth and don’t fall off, Earth and other planets revolve around the Sun and don’t get out of the solar system, stars and nebulas are held together in a galaxy. Now it may sound like a really strong force to you, but it isn’t. Its range is infinite, yet it is the weakest of the four fundamental forces of the universe.

Now you might be thinking why objects have a gravity of their own and how. If you are thinking this, then you are awesome! Even Einstein (you know who he is) thought so and later came up with a proper explanation in his Theory of Relativity.

This is what his Theory of Relativity says, there are 3 dimensions that we already know about, but there is one more, and that is time. These 4 dimensions together make space-time which is like a superfluid. So, anything having mass bends space-time and attracts objects towards it. So, by more mass, it means more bend in space-time and by more gravity, it means more rapidly things will get attracted towards it.

Here is one cool practical example you can do which resembles the working of gravity. You would need 3 persons for it. First, take a bedsheet, then tell person A and person B to hold it from corners and stretch it tightly. Then tell person C to put some weights on the sheet, don’t forget to fold it otherwise it would get torn or just be ready to get scolded by your mother. Let’s say person C puts an object of mass 5 kg on the corner of the sheet. Then tell him to keep a heavier one, like an object with a mass of 10 kg, in the center of the sheet. Then you would notice that the object with more mass would bend the sheet more than the object with less mass. And then both the objects will get attracted towards each other. This is how gravity works. You can also use a trampoline instead.

 

Weak Force or Weak Nuclear Force

Also known as the weak interaction force, most of the readers may not be familiar with it as much as they are with gravity. I found it a bit complicated, but you readers are lucky that I am explaining it simply to you, unlike other websites. This force is stronger than gravity. No need to be surprised, even I was surprised when I first read about it because gravity holds the whole universe together so how come this strange named force, I have never even heard about is stronger than gravity. The answer is simple, this force acts only in short distances, am not talking about 10 or 15 meters or even centimeters, I am talking of a distance which is about `10^{-20}` meters i.e., this force acts on a subatomic scale.

This fundamental force is responsible for particle decay in which an unstable particle (I’ll explain ahead) changes into another particle. This force is responsible for life in this universe and this force is `10^{25}` times stronger than gravity. Not just life but it is also responsible for nuclear fission which fuels the Sun and other stars.

Let’s suppose that you have a stable particle like a neutron, observe it and it will remain the same as it is. But if you have an unstable particle-like Higgs boson, it will break into its constituents in less than `10^{-21}` second, and those particles will further break into their constituent particles. This is how weak nuclear force works.

 

Electromagnetism

This force might also be a bit familiar to you and to understand this you must understand what magnetism and electrostatic force are.

Magnetism is a magnetic force which is a force exerted by magnets and the area in which it acts is called its magnetic field. Every magnet has a north and south pole. Unlike poles attract each other and on the other hand, like poles repulse.

Electrostatic force is also known as electric force, and like gravity is an attractive force, it can either be attractive or repulsive. This force is any attraction or repulsion between charged particles.

So, this ‘Electromagnetism’ force is just the unification of magnetism and electricity. Earlier magnetism and electricity were believed to be two separate forces and then in the early nineteenth century, a Danish physicist named Hans Christian Oersted discovered that electric charge can deflect the needles of a magnet. He noticed the phenomenon and later came up with a finding which tells that flow of electric charge in a wire can produce a magnetic field. And this was when other scientists, because of Oersted, found one thing in electricity that was related to magnetic force, and then the race to unify both the forces into one bigger one was started. In the period between 1820-1871, scientists were working to unify these forces and were finally unified by Michael Faraday and James Clerk Maxwell.

This unification of both the forces into one single force was a major point in science as it extended our understanding of the universe and hadn’t this force been discovered, no development in electrical appliances would have been made. Its range is also infinite like gravity’s but is much stronger than it and weak nuclear force making it the second strongest force of the universe, it is `10^{36}` times stronger than gravity, which is `10^{11}` times stronger than the weak nuclear force.

 

Strong Nuclear Force

This is a force which you study in particle and nuclear physics which is complicated. But now that you have opened my blog, I get the opportunity to explain it to you readers. If you think that this is just a stronger version of weak nuclear force (as the name says), you’re wrong. But don’t worry, I’ll explain it to you in no time.

As you know an atom has a nucleus, and if you don’t then nucleus is a dense region consisting of protons and neutrons held together at the center of an atom. There are protons with a positive charge and neutrons don’t have any charge in them. Now you are wondering nothing is wrong in here, but what if I remind you that unlike charges attract each other and like charges repulse. So how are they held together? Does the nucleus of an atom contradict the fact that like forces repulse and unlike forces attract each other? The answer is no. And this is where the strong nuclear force takes place.

Like weak nuclear force is responsible for particle decay, this force is responsible for holding particles together. Both are stronger than gravity but at a subatomic scale.

Strong nuclear force is the force keeping these like-charged particles together. Now to prove that this force really is the strongest of all forces, the repulsion force between these like-charged particles is about 90 newtons, this force is not much for us, but for particles, it is very strong. If there is no strong nuclear force, these particles would repulse each other at speed of more than 8000 miles per second. This is how strong this force is and is `10^{38}` times stronger than gravity.