The Need for Quantum Theory

The Need for Quantum theory

Philosophically, we all might think that our universe is completely deterministic. This is exactly what scientists thought before the quantum model was hypothesised. A system that is deterministic can be classified as Classical Mechanics (a world where macroscopic objects moves under a set of forces) and since it predicts an object's future by knowing its present or past states with high accuracy, it is thereby, highly built up with strong applied mathematical tools that are really helpful in dealing with these complicated systems. And inevitably, it did a pretty good job in predicting everything other than microscopic objects. So, towards the end of the 19th century, physicists started trying to create classical models of microscopic objects. But its theoretical predictions did not agree with the experimental results. Since, the the theory didn't agree with the experiment, theoretical physicists had to come up with a new theory that agrees with the experiment. With numerous failures in the classical interpretation of microscopic objects, physicists came to a conclusion that there must be a new way of looking at the problem, that might actually help them define the microscopic system.

Quoting Dirac, "We have here a very striking and general example of the breakdown of classical mechanics- not merely an inaccuracy in its laws of motion, but an inadequacy of its concepts to supply us with a description of atomic events" 

The necessity to depart from the classical to the quantum model was inevitable. 

Observational Disturbance

Observation is certainly accompanied by some disturbance. It is impossible to observe an object without interacting with it. Therefore its clear that, there is some kind of universal limitation to our powers of observation. If you had to observe a microscopic object, you have no other way to observe it other than disturbing the object itself. The only reason as to why macroscopic objects can be predictable with high accuracy, is because the unavoidable disturbance is negligible when compared to the size of the object. Determinism applies only to a system that is left undisturbed. In classical mechanics, since the objects are macroscopic, the disturbance is negligible and therefore almost equivalent to the deterministic world. But, in a quantum (microscopic) scale, due to the disturbance, the quantum world becomes indeterministic. Therefore, the mathematics that will be used to formulate this quantum model, will be closely related to the mathematics of the classical model with a lot probability involved in it. And due to the disturbances, nature limits us by allowing the theory to compute only the probability of us obtaining a particular result when an observation is made. 


Classical Mechanics can be viewed as an approximation to quantum mechanics. In reality, the world is actually more bizarre than we thought. And the only reason as to why we find quantum mechanics really hard to believe, is because we human beings were evolved in a classical world. If we were microscopic objects just like the electrons, and other sub-atomic particles. Then we would understand quantum mechanics intuitively. 

"No one intuitively understands quantum mechanics because all of our experience involves a world of classical phenomena where, for example, a baseball thrown from pitcher to catcher seems to take just one path, the one described by Newton's laws of motion. Yet at a microscopic level, the universe behaves quite differently." - Lawrence Krauss

Skepticism is the key to reality

Understanding Skepticism

A skeptic is someone who is inclined to question and doubt any idea until he or she gets the proper evidence to believe in it. Skepticism is sub-divided into two groups -Philosophical Skepticism and Scientific Skepticism. 

Philosophical Skepticism (PS) is an approach that requires all philosophical views to be well supported by logical arguments. Whereas, Scientific Skepticism (SS) is an approach that requires the idea to be well supported by scientific facts. Both PS and SS is very important to a skeptic. Philosophical views give rise to Hypothesis (Proposed theory based on limited evidence) eventually the hypothesis must be proven or disproven through scientific techniques. If an hypothesis is proven through scientific methods then it is considered to be a fact. No one can be 100% sure about anything, in fact science just provides the likelihood of something being true. Every Scientist should be a skeptic, they should put scientific theories to test and check whether the theory holds to be true or not. 

"It doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiment, it's wrong." -Richard Feynman

Faith vs Science

I'm not going to explain the difference between faith and science. Let Tim Minchin's beautiful words speak for itself. 

"Science adjusts its views based on what's observed. Faith is the denial of observation so that belief can be preserved" -Tim Minchin

Faith is one's perspective of what they are willing to believe rather than what they should believe. Who do you think is more reasonable, a skeptic who is willing to change his beliefs based on evidence, even if its against what he used to believe or a person who is bounded by his faith and is not willing to change his beliefs even if evidence is provided?

"Water is two parts hydrogen and one part oxygen. What if someone says, "Well, that's not how I choose to think about water."? All we can do is appeal to scientific values. And if he doesn't share those values, the conversation is over. If someone doesn't value evidence, what evidence are you going to provide that they should value it? If someone doesn't value logic, what logical argument could you provide to show the importance of logic?" -Sam Harris

Skepticism is extremely significant for humanity to advance. We are looking for the answers to both deep scientific and philosophical questions and it won't be possible to find them if ignorance still holds us back.

Debunking Astrology

Basic Introduction to Astrology

Astrology is a belief system made into an elaborate pseudoscience, that basically concentrates the humans as the focal point of the universe. It considers the movement of planets or any astronomical event and relates it to the events in the human world. Astrology consists of horoscopes (An astrological chart that contains the information about the positions of the planets and other astronomical events) that claim to predict a person's personality or their future events.

The need for Astrology

The foundations of Astrology were all debunked more than three hundred year ago, yet it is still taken seriously by a large number of people. The main reason as to why everyone feels the need to check their horoscopes everyday is because of their curiousness to know about their future. Humans always feel the need to be the focal point, they want to feel special and connected. But Science has thought us so much, including the fact that the universe really doesn't care about what humans think. Nature behaves the way she is, it doesn't care whether you like it or not.

People learnt that the earth must be special from religious teachings so they developed models that advocated it. One of these models were Geocentricism, an astronomical model in which Earth is the centre and all other planets including the sun revolved around it. We now know that the Sun is the centre of our solar system and all other planets revolve around it.

Predicting the future is impossible

No one can possibly predict the future. The barrier here is not incapability but a universal limitation that nature sets. The Uncertainty Principle clearly depicts that it is impossible to accurately predict the velocity of a particle if we know its position with high accuracy. It is easy to handle with Classical physics i.e the dynamics of the larger objects. By way of an example, when person throws a ball at you from a far distance, you can accurately predict the movement and catch the ball. It is as though you computed a set of complex differential equations of a system that governed the movement of the ball within few seconds. This seems easy because we were evolved with Classical physics. But Quantum physics (i.e the physics of tiny objects) is entirely different it seems intuitive and bizarre but it has been experimentally tested numerous times. If suppose we could break the Uncertainty Principle barrier and calculate both the velocity and the position of each and every electron of a person. Then it is possible to predict that person's future with high accuracy. But unfortunately, the barrier set by nature cannot be broken.

Why do we consider Astrology as a Pseudoscience?

There has been no evidence that proves the predictions of Astrology. People tend to think that astrology is true because they might have had few experiences in which the predictions were absolutely true. But do they really think they can start believing in something which seems to work only few times? The search for the truth is entirely based on skepticism and continuous experiments. Nature does not change physical constants. If continuous experiments yield to the same answer again and again, we deduce its dynamics, i.e the working behind it and conclude that it must be true.

The Uncertainty Principle is a fundamental limitation that cannot be broken and this is why the scientific community has always considered astrology as a pseudoscience.

"What can be asserted without evidence can also be dismissed without evidence" -Christopher Hitchens. 

Is Mathematics Invented or Discovered?

The Queen of Sciences

Gauss referred to mathematics as "The Queen of Sciences". Mathematics is an universal language that uses logic as its own base for further predictions. We could define any physical object with the help of mathematics. But math isn't just about defining events or objects. Its dynamic, it is as though the language reveals further predictions from the logical assumptions we have taken from the nature. For mathematicians, they think of it as a game. A game which can be assigned, controlled or played with different rules. Rules which aren't compatible with reality. But why does a mathematician have to understand something which isn't compatible with reality? Isn't that just like a child dreaming about Sasquatch? The answer to this is mathematicians really don't care about what relates to the reality, their interests in math is exclusively for their own happiness or the pleasure they get. Mathematicians, can create their own mathematical world. All they needed to do is kick start a world with odd rules or rules of their own interest and play around with them, to find out the governing dynamics. Its beautiful, sometimes messy. The more messy it gets, the more unpredictable the world becomes.

"Mathematics may be defined as the subject in which we never know what we are talking about, nor whether what we are saying is true." -Bertrand Russell

Our universe too is unpredictable but not too messy because of the symmetries and constants. The only reason our world is unpredictable is because of quantum mechanics. If rules of quantum mechanics didn't interfere with our universe then it would be easy to predict ones future with incredibly high accuracy.

The Uncertainty Principle

It states that if we know the velocity of the particle with high accuracy then it is impossible to find the position of the particle with high accuracy. This might sound bizarre, because it conflicts with our everyday experience. If we know the velocity of a car moving, then using Newtonian dynamics we can compute the position of the car to high accuracy. The only difference here is Newtons laws (Classical World)  are applicable only to classical objects i.e objects that are large. The rules of Quantum Mechanics (QM) are only applicable to tiny objects like electrons, protons. QM seems strange only because we weren't evolved to understand it. If you were to shrink yourself to the atomic level, your everyday experience will seem to conflict most of the rules of the classical world.

The uncertainty principle is a well defined mathematical model. Quantum physicists who study the world of QM find it extremely hard to grasp the concepts. In fact Feynman once said "If you think you understand QM, you don't understand QM" The only hope quantum physicists get is from mathematics. They put their theories for tests and gives the exactly the same result as what was predicted using the mathematics of quantum mechanics.

"The mathematical framework of quantum theory has passed countless successful tests and is now universally accepted as a consistent and accurate description of all atomic phenomena." -Erwin Schrodinger

Is Mathematics Invented or Discovered?

I'll be honest with you. No one actually knows the answer to that. But I think it is more likely to be discovered than to be invented. As a skeptic, I have no problem with mathematics being invented. If mathematics was invented then I would be astonished by the fact that the humans were so imaginative in inventing something that happens to work very well with the nature. Math is everywhere and the fact that we can relate/ define to at least some extent and predict its outcomes satisfies me. If mathematics was invented then there must be something or the other that cannot be fully explained by math. But we have no evidence to conclude that, since we still do not have all the mathematics needed for its explanation.

I haven't covered any of these topics in depth but I'll soon post a PDF on the nature of mathematics. 

Gravitational Bending of Light: Energy of Photons

Article Series 3. Continuation of Gravitational Bending of Light and a sequel to Quantum Mechanics of Light.

Mass-Energy Equivalence

This principle revolutionized physics over a century, But unfortunately people now are still unaware of this beautiful equation. The Equation,
                                           
                                                                

signifies that anything that has mass has an energy associated with itself. And the speed of light is a proportionality constant that helps us to calculate their energies.

Special Relativity was the basis for formulating this equation. Even though there are many mathematical foundations to understand this better, I will try to explain it in the simplest language.

According to Einstein, if we travel faster, the heavier we get. This might seem impossible, but it is true and it is happening everywhere. A family traveling in their car, puts on more weight while traveling.
If you haven't inferred it yet, then I would explain it in simple terms. Firstly, what do you need to move a ball from one place to another? Most people will say 'Work'. And they are correct, but what is work? By definition, Energy is the ability to do work. No Energy no work. By way of example, if you kick they ball by giving a specific amount of force, the force given by to the ball, is a direct way of passing your energy to the ball. Now assume that it is an isolated system, and there is no friction. The energy passed on to the ball is its kinetic energy. Since this ball has its own kinetic energy now, it will travel in a straight line forever. Now that Einstein has showed us the relation ship b/w Energy and mass we can understand that this ball's mass should be increased since energy level is raised. Ergo, velocity and mass are also related. This is why the faster you travel, the heavier you get.

Unfortunately, this is the reason why nothing can travel faster than light. Mathematically speaking, if you reach the speed of light, your mass will tend to infinity and you will need infinite amount of energy to keep pushing you to keep you at that particular speed. Therefore, anything that mass is incapable of achieving the speed of light.

You see, that is also the solution of how photons that are mass-less particles are capable of traveling at the speed of light.

Energy of photons

According to Mass-Energy Equivalence, photons who are mass-less are supposed to be energy less. But they aren't and you know it, because you know that plants get their energy from sun's light. If photons do have energy, then does that mean Einstein's equations are wrong? Certainly not.

Quantum Physics gives us the solution for this question. It says that light is an electromagnetic wave that is a form of energy. And its Energy is dependent on its frequency not with mass.

This is one of the famous equations in Quantum physics, in fact this too was formulated by Einstein. He found this relationship when he was working on photoelectric effect. He used Planck's idea. The 'h' in the equations stands for Planck's constant which is a physical quantity that is extremely small and is used mostly in the field of Quantum Mechanics, since it deals with microscopic things.

Deriving the Energy of a photon from Mass-Energy Equivalence.

This video clearly illustrates the notion of Energy of light.
Prerequisites: Introduction to Special Relativity and a bit of elementary mathematics.

Rephrasing the postulate of General Relativity: Anything that has mass, energy/momentum follows the geodesics( Straight line in a curved geometric surface) path of the curvature made by another object.

Ergo, light is can be bent due to any strong gravitational field. Einstein gave this solution to Arthur Eddington, a famous British astronomer to test this theory. He said the stars behind the sun would be seen some where else due to the bending of light. The Theory of Relativity was confirmed by Eddington in 1919 during a solar eclipse. Eddington observed from the images that light from stars passing close to the Sun was slightly bend, so the stars were out of their positions. This discovery made Einstein popular. And finally Newtons theory of Gravitation was thrown out and General Relativity was its fine replacement. 

Gravitational Bending of Light: Quantum Mechanics of light

Wave-Particle Duality

Wave-Particle duality is the rudimentary introduction to Quantum Mechanics. Quantum mechanics is the study of microscopic part of our nature or the study of the actions taking place at sub-atomic level. This is a total contrast to Classical Mechanics in which the study involves only macroscopic level.

Wave-Particle Duality is something like split personality. Electrons sometimes behave as waves and sometimes as particles. It all depends on the situation. In 1905, Einstein published a paper that revolutionized physics, it was known as the photoelectric effect, i.e Electrons are ejected out from metals, when they absorb light in the form of photons in quantized packets. This  proved that light acts as particles and comes in the form of photons in tiny packets as Planck deduced. Einstein was rewarded with a Nobel Prize for his work on photoelectric effect, because it helped physicists understand the true reality of light. Light being both wave and particles how can that be? If this didn't sound bizarre to you, then you haven't actually understand what I just told.

For those who are not shocked when they first come across quantum theory cannot possibly have understood it -Richard Feynman

These actions should sound bizarre because these type of duality never happens in our classical world. Obviously, you don't see homo-sapiens often change into canis (Latin word for dog). We live in a world which is entirely different from the quantum world, If suppose you and your friends shrink yourselves to a tiny electron or a photon you would totally understand how the quantum world works, in fact you would be a part of that world, moving around randomly, obeying wave-particle duality and other quantum postulates.

Now that I've given you an example of a particle situation. I would like to demonstrate a situation in which wave is considered. Imaging a slit that has two slits (holes) and there is another sheet behind it in order to capture the paths of light. If suppose you shoot one particle on the left side of the whole you would get a pattern only on the left side. Similarly, if you shoot another particle on the right side, you would an interference pattern on the right side only. But what happens when you shoot a particle on both sides? Well, obviously according to our classical world throwing a ball on both the slits would result in imprinting both sides of the sheet i.e is the left and the right one.

But unfortunately this doesn't happen in the quantum world. You see we are talking about particles not tennis balls. So, here you see a complete interference pattern that looks like this.

This interference pattern looks this way because in this particular situation light acts as a wave. Just like how when you cause a disturbance to the water it starts creating waves. Now allow water instead of light through those slits, guess what? You will certainly see the same interference pattern. Because water too travels as waves too. The dark spots are the paths of light waves. The white parts occurs due the cancellation of light waves. Now that you know a basic property of light I would like to introduce special relativity in order to explain the gravitational bending of light phenomena. For more information on dual slit experiment I suggest you to check out the lectures given by Richard Feynman in Caltech.

Special Relativity

In order to understand the depth of this topic you will have to read the basics of Special Relativity.
Since I've already introduced you to the basics of special relativity, I will be talking about special relativity from the notion of photons.

Anything that has mass, is incapable of traveling at the speed of light. -Albert Einstein.

Light that is made up of photons. How could photons travel at the speed of light?
You see, according to the postulate, if you moved at the speed of light it would take infinite amount of energy to push you to reach the speed of light, which is impossible.
But if you had no mass. i.e mass is equal to 0. Then you would certainly be possible to move at the speed of light. Photons are mass-less particles and that's the reason why it travels at the speed of light.

The Equation,

was derived from special relativity. This 1 inch equation explains numerous things. An important and famous equation.  According to Einstein, a small mass has enormous amount of energy (Postulate). In fact, this is solution for atom bombs. Scientists used Einstein equations to produce atom bombs.

Lets do some elementary math to confirm this postulate,

From a small amount of mass we get enormous amount of energy.

I haven't still explained the answer to the gravitational bending of light, because this requires a bit of mathematics. I will conclude this with an answer to the topic in the next article.  

Gravitational bending of Light

Bending of light? How is that possible? We all know that light always travels in straight line. In fact light is an electromagnetic radiation that is responsible for the sense of our sight. Without light we would blinded forever.

If suppose light was able to bend in one particular medium, then we all would be seeing each other in different places which results in a messed up optical illusion. This optical illusion doesn't occur to anyone of us because light always travels in straight lines in a particular medium. Obviously the degree of bending of light differs in various mediums. Say if suppose you half dip a pencil inside a Water (Another Medium) you will notice that the pencil would look slightly bent inside the water than in air. This is because due to the deflection of light in that medium it makes it look like its bent inside the water. But what is it that it has to do with gravity? Honestly nothing. I've introduced you to one of the properties of light to prove that the relative index( i.e the number that describe how light propagates through a medium; in this case: how the light bends in different medium.) of air and vacuum are approximately similar i.e The Reflective Index of vacuum is 1 and the reflective index of air is 1.000293 approx. 1. So in Space (Vacuum) light behaves the same as how it behaves in earth i.e it travels at straight lines. Now if there is no bending of light in vacuum then why would I mention the topic as Gravitational bending of light?

You see, from the title itself  you would have guessed that the bending of light is somehow related to gravitational field of an object. In order to elaborate this idea with simplicity I have to introduce you to another abstract concept called General Relativity.

General Relativity

General Relativity is  the curved geometric theory of gravity. As I've already mentioned it before in few articles, Newton's gravitational theory explained everything from the falling of an apple to the earth and other planets revolving around the sun in their own orbit. But it failed in one major thing, it couldn't explain how this gravitational force worked or what it is? Newton himself knew that he couldn't understand it but he left it to god. He said that some mystical force was responsible for gravity. Newton's laws was helpful in various fields but it failed to explain Mercury.
It always failed when computed, many physicists even tried to solve it by introducing many mathematical methods but it didn't work for mercury. But Einstein's General Relativity theory worked really well for it. In fact Newton's Theory of Gravitation is just an approximate theory. General Relativity is known to be the accurate account for gravity. Even though the mathematics of General Relativity are too complicated, its equations are elegant and this one inch equations explains almost everything in our universe. Einstein knew that this theory was correct before even they tested it. Avoiding all the mathematical concepts I'll try to explain it to you in short terms in order to explain how the light bends due to gravity.

Space-Time

Space as we all know has three dimensions, the one everything lies. Up-down, right-left, front-back.
These three dimensions are all familiar to us. But Einstein thought of another dimension he called it the time dimension. Special Relativity his earlier theory published in 1905 tells us that time is not the same for everyone. Unlike Newton who thought of time as absolute, Einstein knew that time is another dimension. The faster you go, the slower your clock ticks. That is why when you move at the speed of light your time relativity ticks even more slower, than the person who is standing still, and after few hours of your trip you will notice that you are much younger than your friend who was standing still. This might be complicated, take a look at this article Special Relativity for more information on it.

You know what? Lets just forget about the notion of this abstract Special Relativity all you need to know is that time is another dimension. Extract from The Elegant Universe - Brian Greene

You would have to know four things in order to meet your friend.
First: Which street?
Second: Which Building?
Third: Which floor?
fourth: What time?

The first three all are three spatial dimensions and the fourth one is the time dimension.
With this idea bare with me for a few moments. Now that you are aware that there are four dimensions. Space-Time is a four dimensional mathematical representation of our reality.
This Space-time is like a fabric, it can be bent, curved, twisted, flexible and many other properties that are almost similar to a bed cloth.

Thought Experiment:

Call your four of your friends and tell them to hold a bed cloth stretched wide. Now take a football and place it in the center of the cloth. You will notice that the mass of the ball creates a curvature around it. Now roll a tennis ball with an initial speed you will notice that the ball will try to take the circular path around the curvature of the football. This what exactly happens in space. Our earth revolves around the sun because of the curvature made by the mass of the sun in the fabric of space-time.

The main idea here is that: Anything that has mass and energy will distort space-time. Since light has energy it is certainly possible for light to bend due to the curvature of a massive object, just like how the moon takes the path of the earth's curvature.

Wait, we haven't actually come to the problem yet? But the main problem here is that how can a light(collection of photons) have no mass at all but still have energy?
In order to understand this we need to indulge into a bit of Special Relativity and Quantum Mechanics. I will continue this in the next Article series.

Wormholes and Multiverse Theory

Einstein-Rosen Bridge

Einstein-Rosen Bridge aka. Wormholes are theoretically developed feature of Space-Time it was theorized on the basis of Einstein's General Relativity solutions. Wormholes is just a hypothetical feature and there are no evidences of its existences. But surely General Relativity predicts it mathematically, and there are chances of its existence but it has been found that it can exist only at the Planck Scale (Energy Scale). 

What are Wormholes? How does it look like? 

Wormholes are basically is passage through two different space-time that could create shortcuts for long journeys across the universe. To picturize this Try folding an A-4 size paper and make a hole at the center with the help of a pencil. Now unfold it and see the point of holes. For instance name the first hole A and the second hole B. If you are living in A and want to meet you friend who is living in B, you will have to walk quite a distance. But if you were to create this Wormhole (i.e fold the paper again) you would have reached B. i.e The point A and B will interest. And those two points are linked with a help of a wormhole. Its just like a long tube but allows you to travel much faster than the usual route. Science Fiction writers are fascinated with this theory and they almost frequently use them in their stories. In fact you can actually link this to the great novel Alice in the Wonderland written by Lewis Carroll ; The Rabbit Hole that Alice can actually be thought as a wormhole which led to another universe (Multiverse).

Multiverse Theory

Multiverse theory is also an hypothetical set that compresses infinite or maybe possible set of universes similar to a huge hamburger stuffed with infinite or maybe finite cheese layers. These type of universes are also called the parallel universe. And strangely according the quantum theory there might be a possibility in which Elvis might be still living and rocking out, or maybe time much be running backwards i.e Entropy( Degree of Disorderness) might decrease with time. Constants might differ in different universe due to that there might not be life forms in some universes. Strangely in our Universe the constants are perfectly tuned in a way that life could form that doesn't mean we are lucky its just an accident that happened and if it didn't we wouldn't have been able to evolve and ask questions about the universe. 

I know that these theories are strange and hypothetical but it has the mathematical proof behind it , as far as that holds experimental researches and theoretical development on that particular theory will continue. In fact the most strange theory ever known to mankind is the Quantum Theory in which strange things happen. For example: Wave-Particle Duality; Light being an electromagnetic wave acts both as wave and particle. This particular theory is certainly strange and different from what we perceive in our world. How could something act both at the same time. Check out Dual-split experiment for more information on Wave-Particle Duality. 

These bizarre things happen almost every time  in the quantum world and it seems strange to us because we are part of the macroscopic world. Surely if we could shrink ourselves with a cosmic quantum crusher (Made-up name) we could  turn into a size of an electron and experience all this by ourselves. 

In fact even-though Quantum theory seems strange it has be tested over and over again and has not been proved wrong even once. All the technologies which we use in our world: From the TV's / Computers to Microchips everything works under the workings of Quantum Mechanics. 
Mathematics is the only language which helps physicists to understand the universe. Without the help of math, it would be impossible for any scientist to deduce the nature. Math is logic. Even-though these theories might seem bizarre it will certainly might become a fact one day. Just like how Nicolas Copernicus theory (The Earth and the other planets are orbiting the sun and not the other way around) is an obvious fact now.

"Pure Mathematics is, in its way, the poetry of logical ideas." - Albert Einstein

"Everything is becoming science fiction. From the margins of an almost invisible literature has sprung the intact reality of the 20th century." - J.G. Ballard

Introduction to Black Holes

Brief History of Black Holes

It is called the black hole because light itself is not capable of escaping its gravity pull. It is formed when a star collapses with a mass of more than 3 times the Sun’s. When it reaches the end of its life, it gets crushed under its own gravity, leaving behind a compact black hole. The first prediction was in 1783, John Michell a geologist, conjectured that there must be a massive body in the universe that has an escape velocity greater than the speed of light. And when Einstein published his general relativity paper in 1915; A German astrophysicist Karl Schwarzchild defined gravitational radius of black holes by using Einstein's general relativity equation in 1916 later known as the Schwarzchild Radius. During that period all these were just theoretical predictions without evidence and many other scientists opposed this black hole theory including Sir Arthur Eddington a famous astronomer who helped Einstein prove his Relativity theory by detecting the Gravitational lens. Later in 1935 an Indian astrophysicist, Chandrasekhar pioneered in the theory of white dwarfs that led him to understand the mass limits of the stars and soon he was able to deduce and tell which star would turn out to be a black hole or a neutron star. This particular limit which he deduced was later known as the Chandrasekhar Limit. After his discovery, John Wheeler coined the term "Black Hole" and since it is black it was unable for the astronomers to find it. But it is certainly possible to detect one because each and every black hole converts its energy to radiation and this radiation can be detected by gamma ray detectors. And the first evidence of an existing black hole candidate was Cygnus X-1. Later in 1994 the best evidence of black holes was provided by the Hubble Space Telescope which captured a picture of a Super-massive Black Hole (Largest type of Black Hole) at the center of our Milky way Galaxy.

We all know that the Luna (Earth's Moon) orbits around the earth. And the Earth and the other planets in our solar system revolve around the sun. But have you ever pondered about the Sun? What does the sun revolve around? Is it just static there or is it moving around something?
The answer is that our Sun and other billions of star in our Milky Way Galaxy revolve around a Super-massive Black hole. The reason behind is similar to the reason behind why the earth revolves around the sun; its because of the Gravitational pull. A Super-massive black Holes gravitational pull is extremely intense; and that is why even the fastest (speed of light) itself is not capable of overcoming the gravitation pull of a Black Hole.

Event Horizon

It is a horizon surrounding a black hole most commonly known as "Point of no return" If you were to go close to the event horizon of a black hole its literally impossible for you to get out from there because the gravitational pull is extremely intense and it is impossible to get out from there because even if you tried to get out at the speed of light it wouldn't work; At that point the gravitational pull will be just too intense and you would experience intense gravity acting on your legs than on your head; there is the vertical stretching and horizontal compression due to which you will turn into spaghetti like shapes this particular phenomena is actually known as the Spaghettification in Black hole physics.


Schwarzchild Radius

What if I told you that if you were to compress Earth to a radius of 8mm it would turn out to be a Black Hole! This might be ridiculous but it is certainly true and there is no physical reason why it couldn't be possible. Obviously it isn't possible to compress the earth to that radius you would need a huge compressor and plus humans aren't dumb enough to turn their home into a sucking black hole!
But this particular way to create a black hole out of earth is certainly possible theoretically. As I've already mentioned before Karl Schwarzchild used Einstein's General Relativity equations to deduce his equations. And the formula which he derived was this:

M- Mass of the object
G- Gravitational Constant
c - Speed of Light

Substituting the Mass of Earth and everything you will get radius as 8mm and this by definition is known as the Schwarzchild radius of the Earth a point at which the earth itself will collapse into itself and form a Black Hole.

The Universe is full of mysteries we should try to understand our level best of these mysteries there is always a solution to everything.

"If you want to see a black hole tonight, tonight just look in the direction of Sagittarius, the constellation. That's the center of the Milky Way Galaxy and there's a raging black hole at the very center of the constellation that holds the galaxy together"- Michio Kaku, Theoretical Physicist.

Introduction to Special Relativity

Relativity

The concept of Relativity is well familiar and quite old. We all are familiar with relativistic events, and we do know that different events occur in different frame of reference. If suppose I was sitting in a moving bus and look outside I would notice the trees passing by rapidly; Similarly if I was standing beside the trees, I would notice the bus passing by rapidly. Everyone is free of accusing the other person in relativity; and obviously the judge would support the person who has his similar frame of reference. We use concept of relativity in our everyday life: "What is the speed of the car? How long will I reach my destination?" The speed of the car to what? Obviously when we talk about its speed we wouldn't say relative to the sun, moon or any other planet. Its a common relative conception that we are referring to the speed of the car relative to the ground. If we were to use more complex relative comparisons then our languages would all be a mess and no one would ever be able to make up anything at right time. The idea of this notion has been discovered long before Newton and its just as simple as arithmetic addiction.

• If your car was moving at 20 m/s at positive x-axis and your friend's car was moving at 10 m/s at positive x-axis then the relative velocity with respect to your car would be 20-10=10 m/s. 

• If your car was moving at 20 m/s at positive x-axis and your friend's car was moving at 10 m/s at negative x-axis then the relative velocity with respect to your car would be 20-(-10)=20+10=30 m/s. The reason why I considered 10 to be -10 is because it was in the negative x direction.

This concept of relativity is too old and it can be noticed in our day to day life. But the problem arises only when we start to introduce light here.

Now, If suppose your friends car is moving at the speed of light i.e (c= 3*10^8 m/s) in the negative x-axis direction and you are moving at 20 m/s in positive x-axis direction. What would be the Relative speed with respect to you?

According to the concept of Relativity, you would apply the rule and notice that 20-(-c) = 20+c m/s
where c is the speed of light.

Now the problem here is that when it was experimentally determined the answer was just c.

How could that be possible? Isn't it violating Newton's understanding of relativity? So does it mean that Newton is wrong?

No. He isn't wrong but he certainly made a mistake in believing in absolute time i.e Time is the same for everyone; It is relative like motion.

Before Einstein's period, physicists used believe in a medium known as the Ether. The medium through which light travels. So in order to find out the truth about the ether, they thought of an experiment that would allow them to calculate the precise relative speed of light, i.e if they noticed the speed of light decreasing, then there must be a medium that was acting relative to this and this medium should be the ether. As soon as this was suggested Michelson and Morley, the two scientists went out to explore for the truth and the result was just the speed of light. Since the speed of light wasn't changed they decided to abandon the idea of Ether.

Special Relativity

This idea of speed of light always being constant even when added or subtracted with other relative velocity annoyed all most all physicists. In fact, the main reason why they were really annoyed was because they didn't follow the symmetry between electromagnetic waves and Newton's relativity. (I'll talk about the symmetry of electromagnetism and Einstein's Relativity in the upcoming article).

Lorentz, an eminent physicists played a very vital role in the history of special relativity. He derived the appropriate formula for this situation. Even though the problem was quite solved it still had open wounds. To fully recover the idea of relativity, Einstein, a well known theoretical physicists came in and introduced an idea that was mind boggling. He called his new theory, the Special Relativity; the special thing about it is that it changed the way we understand the universe. In his new theory

• Time isn't Absolute; Its different for different person at different frame of reference. 

It is certainly important to understand the math behind it but I don't have the time to explain it here. But I'll surely attach a link to this post regarding deeper meaning of special relativity with mathematics involved.

Einstein basically used Lorentz equations known as the Lorentz Factor and used it make out his own understanding of light and it turned out that all the Newton's equations is just an approximation and the original equation was quite different. In order to theorize the new corrected Einstein formula; Einstein just plugged in the Lorentz Factor into Newton's equations and found that it satisfied everything and brought back the symmetry of  Electromagnetism. (Just FYI: Plugging equations wasn't all he did. He had to theorize his ideas with the help of complicated mathematics). All of physics was saved by a 26 year old German clerk working in a patent office. This elegant equations gave rise to different ideas and throws out our current common sense.

For instance: What if told you that you would age a lot slower when you reach the speed of light!

Einstein's equations tell us that if you were to travel close to the speed of light time will relatively start ticking slowly for you than the others who at rest. Its quite hard to wrap your head around this.
For instances, lets take a ride through Einstein's thought experiment:
                                                                                   

Suppose you are now travelling at the speed of light according to Einstein's Relativity equations your time will relatively slow down and you would age very slowly. But your friend on earth will be ageing normally. Since your ageing process has been slowed down when you come to a stop you will notice that your friend would have aged more and you less. Now what does that tell you? You have successfully traveled to the future. Time travel in the future has been proved by Einstein theoretically. But Time travel in the past isn't possible.

Why time travel to the past isn't possible? This is because there are too many paradoxes. The most famous paradox is known as the Grand Father Paradox; Its a thought experiment in which if suppose you were to travel back in time to your grand father's period and kill him; you wouldn't have been born and if you weren't born how could you have traveled back in time and killed your grand father?
Time travel in the future has been confirmed by numerous experiments but time travel to the past has too many paradoxes.

If you want to know more about Special relativity and how it works download the PDF here Introduction to theory of Relativity This books covers both Special Relativity and General Relativity.
And for Lectures on Special Relativity check the video tab of my blog.

Theory of Everything-3

Theory of Everything

Its the grand unification of all the forces known to mankind, from the Quantum level to the Macroscopic level. Its an abstract theory which describes almost everything in the universe in just one single mathematical equation. This mathematical equation might just look like E=mc^2 equation. An equation which is just 1 inch long but gives us vast information about the energy-mass relation. Physicists all around the world are contributing to this theory. And Just as our other physics theories, this one too has sub candidates. The main candidate that helps in constructing this extraordinary theory is the String theory. This theory states that everything in our universe is made of oscillating strings. Each and every vibration of a particular string corresponds to the behavior of a particle.

"String Theory describes energy and matter as being composed of tiny, wiggling strands of energy that look like strings. And the pitch of a string's vibration determines the nature of its effect."-Roy Williams

Unfortunately, the problem with this theory is that it is not experimentally proven. Because of this, many physicists criticize this theory by calling it a pseudoscience. The reason why it is still not experimentally proven is because we are not yet capable of magnifying a particle to its lowest level; in other words we just don't have the technology to do so. But that doesn't mean that the theory is false and there should be an end to this quest. Maybe one day we might achieve the required technology that is capable enough to find the wiggly strings. String theory has been theoretically proven with the help  of mathematics. We should encourage these hardworking string theorists rather than demotivating them.

Mathematics has always been our language to describe our universe. I would describe Mathematics as an Universal language. A language which helps science to describe events occurring in our Universe. String theory should not been considered as a pseudoscience. People thought Einstein's General Relativity theory was crazy. Only few physicists that time who believed in mathematics could appreciate his works. He deduced it all with just a pen and a paper. He believed that math was the only key to unravel the mysteries of the universe. But It took approx. 100 years to prove his theories were experimentally right. Maybe String theory might also work the same way.Einstein's dream was to unify all the forces and understand the universe completely and this has been achieved by today's string theorists.

Soon after few decades we might be able to unlock the mysteries of big bang and the black hole with the help of this theory. And who knows Science fiction might one day turn out to be our reality.

"Science is the process that takes us from confusion to understanding.." -Brian Greene.

Theory of Everything -2

Sequel to Grand Unified Theory -1

Despite all his greatest achievements, Einstein wasn't satisfied. He was still looking for the ultimate answer. So he set on a goal to achieve this by relating his new picture of gravity ( General Relativity) with Electromagnetism(EM). During the early 19th century, Electricity and magnetism were scientists great interests. Both Electricity and magnetism played an important role together and was also helpful in further telecommunications systems. It was so important that it demanded a specific unification. For instance, if suppose you are in a hill station during a thunderstorm you will probably get the idea of how electricity and magnetism are closely related. i.e the thunder strike creates a magnetic field that will  show abnormal functions in your compass. This field was unified as the electromagnetic field and was developed using the language of mathematics. How fascinating is it to see just a four line mathematical expression showing the relation b/w electricity and magnetism. This equations were deduced by Maxwell. Just as how Newton revolutionized physics with Gravitation, Maxwell has equally helped in understanding our universe. Einstein believed that this unification of both his view of gravity and electromagnetism would give birth to the answer to everything. This step was the first try on understanding our universe completely. He was one of the physicists who wanted to know the mind of God(entire picture of our universe). In fact this is the goal of today's string theorists; To unify almost everything within one simple theory - From the big bang to the black holes.

As Einstein started working on his theory he found a major problem in unifying it, he noticed that there was a huge difference b/w the strength of the Electromagnetism and Gravitation. i.e the strength of EM force being far more stronger than the gravitational force. Wait! How is that even possible? Gravity is so strong that its even capable of bending light! Gravity probably should be the strongest force. Yes, that is partially right but it is a known fact that it is certainly not as much stronger than EMF(Electromagnetic Force). In fact EMF is billions time stronger than gravity. The reason behind this lies in the microscopic level and is also the reason why we don't fall right down into the center of the earth. It might seem quite strange but its the truth. Everything in our universe is made up small bits of atoms, in which the -ve electric charges are present in the outermost shell of the atom. Now remember, the force which keeps you on the earth's surface is EMF, because there is a strong repulsive force between the two -ve electric charges.(One being the electric charge of yourself and the other being the earth's surface's charge). Imagine the repulsive force created to sustain almost each and everything in our earth. In layman's language, we all know that gravity pulls you down to the earth. But guess what now you know that EMF creates a massive repulsive force which prevents the gravitation pull towards the earth. Now, do you think gravitational force is much stronger than EMF? No, certainly not. This was the underlying reason for the major problem in unifying them both.

To be continued in the next article-Importance of mathematics in physics and Quantum Mechanics. 

Theory of Everything -1

Einstein's Dream

The Grand Unified theory is one simple mathematical model which expresses all the forces that governs the universe, from the quantum level to the macroscopic level. Its a quest in merging both Quantum Mechanics and General relativity. And it is of course one of the greatest unsolved problems in physics. Einstein's dream was to achieve this stage. But unfortunately, he wasn't able to. But physicists of our generations has found a candidate which might give us an ultimate answer.

General Relativity 

General Relativity is geometric theory of gravitation published by Albert Einstein in 1916. Well, we all might be familiar with the Newtonian Gravity. But there is far more interesting than that. The attraction force between two bodies as Newton predicted it as the mysterious gravitational pull was well known to Albert Einstein than the father of gravity. Albert theoretical found that the curvature of the space-time is responsible for gravity. Space-Time- A four dimensional world where space is 3-D and time as 1-D. To get a better understanding of it Click here Space-Time (Article on Space-time continuum).

Physicists were dazzled after reading his paper. But some theoretical physicist thought this idea was a misconception , whereas the others wanted it to be experimentally proven as to be believed, because science has always been this way. Only if it was experimentally proven or witnessed, people will start believing in it. In fact, Richard Feynman has quoted that "It doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiment, it's wrong".

Physicists wanted to know the reality behind it. So they began exploring and started working on constructing a framework which shows us the existence of space-time curvature. After everything they decided to launch a satellite -Gravity Probe B(GP-B) on 2004. The mission's aim was to measure the space-time curvature near the earth. And the results were finally proved that there is existence of space-time fabric and the curvature of space-time fabric is due to the presence of mass which explains the gravity taking place there.  Einstein was right. All physicist were amazed by this true fact. After almost 100 years Einstein's theory was proved right experimentally. And far more than that Einstein was even able to calculate the speed of gravity i.e the speed of gravitation waves in the space-time fabric. In general relativity theory the speed of gravity was equivalent to the speed of light in vacuum. The paper explained all the forces that governs the macroscopic world. Its quite strange that Einstein got Nobel prize for Photoelectric effect rather than this beautiful mathematical model.

The idea of General Relativity was thought by Albert when he pondered over light and was focusing on his earlier paper i.e Special Relativity which was published in 1905. Special Relativity deals with the speed of light. It says that speed of light is an universal constant, it does not change relative to anything.

Most of the people know that the light travels in a straight line. But that isn't always right, light bends due to gravity. It seems quite bizarre but it is the truth. As I've already mentioned before, scientists always look for evidences for the truth- as General Relativity predicted it. This is apparently known as the Gravitational lens. This is the phenomena explains the bending of light. This theory was confirmed in 1919 during a solar eclipse, when Arthur Eddington, a British Astrophysicist who observed the light from stars passing close to the Sun was slightly bent, so that the stars appeared slightly out of position. Einstein once again was right. He almost predicted most of the things which explained the macroscopic level of our universe. This was a huge turning point in understanding our cosmos. A legend who predicted most of the things theoretically. The only tool which he used to explain all these extraordinary and fascinating theories was Mathematics. All started from this Genius, who worked as patent clerk in a Swiss Patent office in 1903...

To be continued in the next article related to Quantum Mechanics and String theory.

Space-Time

The very basis of knowing how our universe looks like

If suppose we remove each and everything in our universe. From the very macroscopic level to the microscopic level. What would you call it? A void? Many of them would call it 'Emptiness'. Yes that's right but it is also wrong. If you look deep inside the so called 'Nothing' in our universe. It would be just the Space. Space as existing in three dimensional.

But our universe isn't just 3-Dimensional. Time is a dimension in which events occur. And this event's occur only when there is space. So if I ask you, with what respect to are you moving? No matter what frame of reference. Even if your sitting in one place right now. The answer is we all are moving through space-time. A 4-dimensional universe, where space existing in 3-D and time playing the role as fourth dimension. In cosmology, the concept of space-time combines both space and time to a single abstract universe. Mathematically saying, its known as a manifold consisting of events which are described through co-ordinate system. Picture infinite no. of  lines and no. of other lines which are passing through it perpendicularly. We come up with a picture which has numerous no. of square shaped boxes. And this is what we call as The Space-time Fabric. This extraordinary fabric has the ability to fold, curve, vibrate etc. Everything in our universe lies on this space-time Fabric. This might be a complicated topic, but knowing the basis of how it works isn't a waste of time. It at least gives you an idea of how our universe looks like.  

Gravity is a shape

We all know that, Newton is credited for his works on gravitation and the story of the apple falling on his head. Newton's law of gravitation states everybody in our universe is attracted by each other with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. Even though Newton discovered gravity, he failed to understand it deeply. He didn't know what exactly was this mysterious force which made the apple fall. He couldn't understand how his own theory works. But Einstein, a very well known theoretical physicist was the one who understood what gravity was completely. His works on general theory of relativity gives us the best understanding of how the gravity works.

If suppose gravity isn't a force then,

Have you ever pondered how our earth revolves around the sun actually?


Einstein view of gravity explains it all. A curvature of the space-time fabric occurs due to the presence of the sun. The sun's mass acting on the fabric, tends the fabric to curve and create a gradation. Now, imagine as if you are rolling the earth towards the sun. Due, to the presence of the curve, the earth keeps revolving around the sun. And the curvature which took place is very well understood as the gravity itself acting as a shape. Therefore, gravity is caused only because of the space-time warp.

A picture depicting the working of the gravity. The space-time warp (Bending of the space-time fabric) caused due to the presence of the mass of the earth, which tends the satellite to move along its orbit.This is considered to be one of the best workings of Einstein. But he has done far more extraordinary than this. We still have numerous things to find out about our universe...We just know only about 1% of it. I hope you all were able to understand it. If not, I'll soon upload a animated video clip in the video tab, which explains it well enough.

The Universe in a Nutshell

What has physics done to me lately? Does it help me in my life? and the answer is Yes. The study of nature is considered to be the only way to understand our universe. Back in B.C's most philosophers believed in Flat earth model, instead of the current model, which is the Oblate spheroid ( rotational symmetric ellipsoid ).

Once a well known scientist (Bertrand Russell) gave a lecture on astronomy, he explained all the orbitals and the movements of the moon around the earth and the earth revolving around the sun. At the end of the lecture an old lady stood up and said "What you have told is rubbish, the world is a really flat surface and is supported on the back of a giant tortoise". The Scientist gave a smile and questioned " What is the tortoise standing on?". "You are very clever young man".

This short part is an extract from the book-A brief history of time.( I wrote a review on this book).

The thing behind this is that the old lady just believed in things which made sense, but she didn't give a try on understanding what she was actually believing.How was the earth just staying there in its orbit without falling? The reason behind this is the Gravitational force. The law of gravitation states that every object in the Universe attracts every other object which is directly proportional to their product of masses and inversely proportional to the square distance between them. This law was stated by Newton, a legend who discovered gravity and well known for the the paper he published. His paper 'The Mathematica Principia' is considered as one of the greatest papers of all time. It was hard for him to calculate the gravitational force between objects and many other problems in other topics using elementary mathematics. So he developed a new level of math 'Calculus' which helped him solve the equations. Calculus was both developed by Newton and Leibniz . His works have been published in many different book and his major contributions had lead to Classical Mechanics.

In Physics, it is really hard to relate tiny atom in an apple with a huge planet in our galaxy. So physicists figured out a way to extend this study which is known as the Quantum Mechanics. Classical mechanics is the study of macroscopic level and Quantum Mechanics is the study of microscopic level. If we get a chance to link Quantum Mechanics with Relativity theory then we might have finally completed the quest on finding the theory of everything. But the problem is that if the theory is too complicated, then we might want to sort it down and split the topics again to make others understand the way it is.

I recently read this book - Six easy pieces by Richard Feynman and he has explained the importance of the atom hypothesis in the introduction part really well.

For Example (Feynman) -
If suppose the current generation snapped and we all have 5 minutes left for the death, but there are possibilities of life in the land and you have given a place to store something for them. If this is the case and if you choose knowledge over everything. Then which is the most preferable knowledge you would like to share it with the next starting generation?
The answer would be the atom hypothesis.
The atom hypothesis - Everything in the universe is made of atoms.This is the basic fundamentals of science. The clue given to them would be- Everything is made of atoms, which is in perpetual jiggling motion and its characteristics might change if you experiment with them. This particular clue should be depicted as a drawing so that it is well understandable to them. This might take a few years for them to understand it, but their science will be developing more rapidly than ours.

A better definition of Science

Science is said to be the study of nature.
To understand this, consider a chess board which is our universe here, and the moves are made by the God. The moves he makes in order to save his king, we have to figure them all out. Each move is consider to be a change in the universe. For instance, moving a bishop diagonally results in change in climate (rain). So here we assume our universe as a chess game played between Gods, and the moves made by him in the game are the changes in climate. So we deduce all the rules from the chess board in order to predict the future weather. But if something strange happens that the moves have changed their rules in the chess game and you try so hard to figure it out by relating it all the rules deduced but you just cant get them related to the new move. In this case, we come up with a new rule which is said to be Castling in the game. Here's a twist and now it is said that all the rules cannot be correct, when time changes the rules or laws keep changing.

Theory of everything

In 1995, when Albert Einstein passed away. Each and every newspaper published the picture of his desk.
And they quoted it as "The unfinished manuscript of the greatest work of the greatest scientist of our time". The unfinished manuscript in this context mentions the Theory of everything. The dream and the goal of every cosmologists is this theory of everything.What exactly does this theory of everything mean?

It's an equation which summarizes all the physical forces in the universe and this equation should be as simple as possible. This theory is said to be the ultimate theory, we might even get to predict the future. To understand this topic deep, we must know the concept of M-theory (Membrane theory) which is quite complicated. So I'll drop the concept here. If you have interest you might wanna take a look over it, its quite interesting but I cant understand it. To learn this we should be familiar with classical mechanics, quantum mechanics and Cosmology. But you still can try getting a vague idea of what string theory is.

Conclusion
Aren't you curious to know how our universe works? What is the need of science in our life? Why cant we travel to the past or the future? Science is the only answer to all these questions. In fact we live in a world in which everything around us is related to science. (The tables, laptop, people etc.) We all are made up of infinite number of atoms which is relatively negligible when compared to the infinite number of starts in our galaxy. And physics is one of the sub candidate of science which might help us get to know the real concept of the Universe (The Ultimate theory of Everything).

Review on A Brief History of Time

Genre: Cosmology (Study of universe)

This book was written by Stephen Hawking, one of the greatest cosmologist and theoretical physicist after Albert Einstein.

"His is a brain of extraordinary power"-The New York Review Books.

Even though he is suffering from Motor Neuron Disease, which unfortunately paralyzed him for the rest of his life, he is still free in his mind and has the capability to think to any extent. He was fascinated by science during his childhood. Once, when Stephen was young he asked his father "How does the universe work?" and his father told him that he will let him know it soon. Of course he didn't know the answer to it in fact non of us know it either. And when he was recently interviewed he quoted that he is still on a adventurous quest to find the answer.

“My goal is simple. It is a complete understanding of the universe, why it is as it is and why it exists at all.” -Stephen Hawking

The only key to understand it is the Ultimate theory of everything a.k.a A simple theory which explains everything in the universe. This theory should be so simple that even a normal layman should be able to grasp it. And one of the candidate falling below which stood firmly was the M-theory aka Membrane theory. It might seem complicated if you have no prerequisite idea of it. But its fine, Go browse related to it or else the best way to understand these are by knowing the fundamentals first. So start reading this book if you would like too.

“We are just an advanced breed of monkeys on a minor planet of a very average star. But we can understand the Universe. That makes us something very special.” -Stephen Hawking

Stephen hawking is one my inspirations. During his PhD on astronomy he worked on his research paper, which lead him to the theoretical prediction of Black hole radiation, now known as the Hawking Radiation. Hawking radiation is the radiation emitted by the black hole this was predicted mathematically by Stephen Hawking and his assistant.

This book gives you an idea from newton's time to Albert Einstein's period. "From the big bang to the black holes" as quoted in the book. He makes us fall deeply into the book where the question arises to yourself - How do we understand our universe? Why do we live here? What is the need? How does the universe work? He asks a lot of  questions which makes us THINK. I'm pretty sure that If you start reading it you will be greatly influenced by his writings. He simplifies the complicated topics just to make sure that each and every layman is able to understand it.

The introduction was written by Carl Sagan, a popularizer of Science, theoretical physicist. The TV show "Cosmos" was presented by him. This is a Science and technology genre(Cosmology). Sadly, I could finish only one episode of the first season. Its a 1 hour show but worth it. I should probably start watching them later and maybe then I can try giving you all a vague idea on the mysterious physics theories he talks about. As far as I know this show is best known to give a better understanding on the theories by relating everything to the examples of nature elegantly.

Now back to the book.Stephen starts off really well by making us question ourselves. This book was really inspirational to me. After a few chapters he comes up with a chapter named 'The Uncertainty principle' you all might have learnt it in high school. That is, it is impossible to find accurately the position and the momentum of a particle at the same time. But it is also believed that suppose if it is possible to find both accurately at the same time then it os possible to predict the future approximately. That is, if you know the particles position at any time then it can be said that we we will be knowing its position even after 100 years or 10^6 million years. He gives us all an understandable gesture of it in the book.

I loved reading this book. it was a Page turner, he fascinates us with many facts which makes us desperately know the answers.

If your really interested in cosmology, then I suggest you to read this book first.You can also find a Pdf of it. Google it. I'll soon write more articles on cosmology.