The Ultimate Guide To The Forces Of Nature
Have you ever wondered how the mechanism of the universe works? What is its mechanism? Is it like a clock with many gears? (Some thought that!)
What is the reason Earth revolute around the Sun? Why do we see the sun daily? And see the moon at night? When a bat hits a ball then which force is exerted?
No worries mate. This guide is just made for all these questions. Once through this guide, one can explain any action on the face of the earth with a force. Let us start!
Four Types of Forces
We know of these four forces of nature:
Strong: Holds Quarks together in Protons and neutrons. Hold Protons and Neutrons together in nuclei.
Electromagnetic: Hold together atoms, molecules and larger bodies, including humans.
Weak: Causes Radioactive Decay.
Gravity: Holds together massive bodies of the universe and makes apples fall on earth!
Now, first thing’s first:
Sir Isaac Newton established the concept of forces as agents that change velocity. His first law states a principle that was discovered by Galileo:
Without a force, velocities do not change; objects at rest remains at rest and objects in motion remain in motion.
His second law states that when a force is applied to an object its velocities changes – it accelerates:
Force = Mass times Acceleration
F = m x a
Acceleration
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| Don't Get Inspired!!! |
Acceleration is how rapidly velocities changes. For example:
Top Dragsters change their velocities from 0 to 330 miles per hour (mph) in 4.5 seconds. That’s an acceleration of 74 mph per second, over 3 times the acceleration of the gravity on Earth’s surface! (Oh Yeah!)
Working Mechanism
But Akshat, you ask, how do forces work? It’s not hard to understand how a bat applies a force to a ball – through object contact.
At a microscopic level “contact” means atoms in the bat are squeezed against those in the ball the electrons in these atoms repel one another thus forcing “the ball and bat apart”.
But Newton was unable to explain, as was everyone else before Einstein, how the Sun could exert a force on Earth across 93 million miles of empty space.
This mysterious effect was called action-at-a-distance. No one, including Newton, was compatible with an unexplained, Non-Contact force, but because his equations gave the right answers for the motions of apples and planets, they were accepted and held sway for over two centuries.
The Modern View of Force
The modern view of force is:
(1)The force between any two objects is the sum of the forces between all the individual particles of one object and all the individual particles of the other object.
(2)The Force between any pair of particles arises because they exchange another type of particles called boson.
This modern view of forces comes from the branch of physics called Quantum Field Theory and incorporates the concept of virtual particles.
Bosons: Carriers Of Forces
Bosons are named in honor of Indian Physicist Satyendra Nath Bose, who in 1929 described a key Quantum Mechanical aspect of the behavior of these force exchanging particles.
Bose’s idea was quiet novel, and as he was not known and not European scientific journals refused to publish his work.
Refusing to be denied, Bose sent his paper to Einstein requesting his endorsement. Einstein saw great value in Bose’s ideas.
He translated Bose’s paper into German, wrote his own supplementary par expanding on Bose’s ideas, and ensured both papers were published together which are now referred as Bose-Einstein Statistics.
Bosons Associated with Forces
The strong, electromagnetic, and weak force each have their associated Bosons. Quantum Field Theory is effective in dealing with all forces except Gravity.
Field theory presumes an exchange Boson for gravity, named the Graviton, but that has not been yet detected, and calculation based on graviton exchange do not yield sensible results.
Einstein’s theory of General Relativity (theory of gravity) is very effective for large, macro-world objects but it is not a Quantum theory as is required in Microworld.
Closing this theory gap is one of the highest priorities of modern physics.
Only with an effective theory of gravity that works both n macro-world and micro-world, will we better understand the center of black holes and the moment of the Big-Bang.
Feynman Diagrams
The schematic in the above figure provides insight into the physical process and is a starting point of quantitative analysis.
It is called a Feynman diagram in honor of its inventor, Nobel laureate Richard Feynman. In this figure, two electrons enter from below and interact by the means of electromagnetic force.
The left electron emits a photon that the right electron absorbs; the photon changes the velocities of both electrons, resulting in a force. (Just get a visual picture of it in your mind, focus!)
The right electron can also emit a photon that the left electron can absorb. As a matter of fact, there are innumerable diagrams of ever greater complexity for the introduction of two electrons.
Feynman’s rule make it easier to systematically list the possible diagrams, identify the important ones, and compute their effect.
Comparing Apples and Oranges
Quick question, tell me the difference between an Apple and Orange.
Till you figure out the difference, let's compare the four forces. Is it a loop, don’t you think? It is same as the difference between an Apple and an Orange, two completely different things.
But to feed your curious bug, we can analyze the strength of these forces. Let’s assign the strength 1 to weak forces, shall we?
Strong: 10,000
Electromagnetic: 100
Weak: 1
Gravity: 7 x 10-34 (0.0000000000000000000000000000000007)
Oh, poor gravity, you see the gravity is the weakest forces of all but its range is the largest. Gravity’s strength is less than a trillionth of a trillionth of a trillionth of that of the strong force.
Conclusion
Now we know that Bosons are the particles which carry force. There are different types of bosons for different types of forces. Four types of forces: Strong, Electromagnetic, Weak, and Gravity. We learned Feynman diagrams and how a force is “created”. We learned about Quantum Feild Theory.
Looks like its time to go. But don’t forget the spirit of forces is still after you. You can’t skip it. You can’t miss it and you definitely can’t ignore it. Will talk to you soon in episode 2 and episode 3.
Do you have any questions? Just post them below in the comments section. I have answers (maybe).
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