Equation of a circle passing through three given points [A.R. Khalifa's Formula]

A. R. Khalifa (Azizur Rahman Khalifa), Professor of Dhaka University, deduced a simple formula for determining an equation of a circle which passes through three (given) points. For this reason, the formula is also known as A. R. Khalifa's Formula.

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Heisenberg's Uncertainty Principle

In a game of Cricket, a form of light called radar is often used to measure the speed of balling. The radar is shot at the ball to measure its speed but this radar never changes the direction of the ball. If it did, it wouldn't be used in the game.

But it is a different case in the world of atoms. The subatomic particles inside the atoms are so small that light waves bouncing off atoms causes them to change direction and speed, and in some case even knocks the electrons in the atom away from orbit.

So no matter what these subatomic particles collude with (light, other little particles, air molecules etc.) it always changes the position and/or speed of the particles.

This makes it impossible to measure the position and speed of subatomic particles simultaneously. So we can say that we can only measure the speed and position of subatomic particles within a certain range or within a certain uncertainty. This is called Heisenberg's uncertainty principle. 

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The Big Bang Theory

This is currently the most popular theory explaining how the universe was created. According to this theory, The Universe had its origin from a giant explosion known as the Big Bang. The matter flung out from the explosion condensed into galaxies that are still rushing outside. A common analogy explains that space itself is expanding, carrying galaxies with it.


The big bang theory received its strongest confirmation when the "cosmic background radiation" (the glow left after the explosion itself) was discovered in 1964 by Amo Penzias and Robert Wilson.

In 2003, NASA's Wilkinson Microwave Antisotropy Probe made measurements of the temperature of "cosmic background radiation" to within a millionth of a degree and came to the conclusion that  our Universe is 13.7 billion years old and the first generation stars began to form a mere 200 million years after the Big Bang.

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Higgs boson Particles

Higgs Boson is a theoretical particle deduced as a result of the ‘Standard Model’ of Particle Physics. Some call it ‘The God Particle’ as it is considered to be the center to our understanding of the nature of matter. But to understand about God Particle, we first have to understand the standard model and all that’s related to this.

In particle physics, the standard model is a widely accepted and extremely accurate framework which describes the universe of matter (fermions) and force (bosons). Consequently, the standard model is sometimes referred to as ‘The Theory of (almost) Everything’

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Schrödinger's Cat

A principle of the quantum theory named "superposition" states that if we don't know what the state of an object is then as long as we don't check, the object is actually in all possible states simultaneously. 

Erwin Schrodinger proposed a theoretical experiment in which a cat was put in a box with a bottle of poison and a tiny amount of radioactive substance and a Gieger counter (a device for detecting radiation). The radioactive material had a 50:50 chance of decaying. The Gieger counter was designed so that when it sensed the decay of radioactive material, it triggered a hammer which was poised to break the poison bottle and kill the cat. But as long as the box stays closed, we wouldn't know whether this has happened or not. So according to quantum law and superposition of states, the cat is both  alive and dead at the same time.

But if we take a look in the box, the superposition ceases and the cat is either dead or alive. So as the observation affects the outcome, the outcome doesn't exist until the observation is made.  

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