Saturday, 23 June 2018

STRING THEORY : THE THEORY OF EVERYTHING

         STRING THEORY : THE THEORY OF                               EVERYTHING



The world we live in is rapidly changing with resources being depleted and consumers being increased. The climatic conditions are getting worse and everyday we discover something new that may pose threat to our mother earth. So we must keep expanding our knowledge of universe to discover new possibilities of our existence in this universe or i should say in this multiverse.  For acquiring a better  picture of this universe, we must posses a better understanding of its fundamentals or building blocks. We need to bridge the gap between our classical world and the quantum world and the bridging must be done by a single theory like a single thread that binds all the pearls of a necklace together. 
So to present a better and radical picture of this universe many theories were proposed and examined by renowned names in the field of science. Their main purpose was to combine all the four fundamental forces of nature (gravitational force, electromagnetic force, strong and weak nuclear force ) so that they may be explained by a single theory, a single law to govern the universe. The most successful theory among them is STRING THEORY. 
Origin of this theory can be traced back to 1968 when Gabriele Veneziano accidentally discovered a 200 year old mathematical equation that seemed to describe strong nuclear force and he published it. This equation faced some advancements and later came to be known as string theory. Physicists could never accept it totally because its predictions and assumptions were too radical to be accepted furthermore it wasn't possible to prove it experimentally. But some scientists took a leap of faith and here it is, one of the best theories we have today.
It predicted the existence of one dimensional vibrating strands of energy called strings and those strings required extra dimensions of time and space for its movement. It required 9 dimensions of space and 1 dimension of time for its movement often called as degrees of freedom with all these extra dimensions being curled up together and present at each point in space. These strings are fundamentals of universe and they are so incredibly small that if an atom were enlarged to the size of the solar system then a string would only be as large as a tree. The different ways in which these tiny strings vibrate gives different properties to particles. Each particular pattern of vibration gives birth to a particular property like charge, mass etc. It also predicted some mysterious mass-less particle that was never seen before in nature. These particles seemed to be describe  gravity at quantum level (quantum gravity) . Later those particles were discovered to be "graviton". 
The mathematical equation of this theory had 10^500 solutions and also there were 5 different versions of this theory each one facing different anomalies. In 1995, at the university of Southern California Edward Witten forwarded his work in which summarized all these versions into a single one known as M THEORY though no one knows what that M means, also called as unified field theory.  He believed that these different versions of theory were nothing but different ways of looking at a single theory. M theory predicted even one more dimension of space making the total sum 11 (10 dimension of space and one dimension of time). The newest version made the picture clearer and eradicated anomalies that followed string theory. It gives a nice try to unite general relativity and quantum mechanics.  M theory  allows a string to stretch to a membrane or just BRANE that could be 3 dimensional or even be of more dimensions and with enough energy it could grow to the size of universe. This theory also supports the existence of parallel universes (if universe is considered a slice of bread then there must be other slices of bread when we talk about a loaf of bread ). The universe is considered as a membrane and everything sticks with it allowing nothing to escape. 
                         


It predicts that all the matters comprise of open strings having their both ends tied to the 3-d membrane so that they can't leave it but graviton are made of closed vibrating strings allowing it to travel other dimensions and universes which of course gives an answer to a very famous question that '' why even after being so powerful  and dominating force gravity seems very weaker than other fundamental forces of nature? '' . The answer is obvious, escaping of universe by graviton dilutes the strength of gravity. 
Further the supporters of string theory propose that the possibility of communication with other civilizations can be accomplished with these gravity particles in the form of gravitational waves.




 It also tries to explain what caused the BIG BANG using the concept of multiverse, predicting it to be caused by collision of universes or the fissioning of universes(if we consider our universe to be a soap bubble then we know that a new soap bubble is formed when two bubbles merge and two bubbles are formed when a single one splits, big bang can be considered either to be splitting or merging of universes and we are trapped in the universe like insects are trapped on the surface of a soap bubble  ) .
Today we have some prominent physicists working upon this theory and one of them is Michio Kaku, a professor of theoretical physics is a specialist in string theory. His strong belief in this theory made him devise a single short mathematical equation for this theory- 
               
            

This theory still keeps surprising physicists with not only its predictions but with the very large portion of our world(both , the one we see and the one we don't) it can describe.  
                                     
                                            Thank you
                                               
   

Sunday, 10 April 2016

Light:basis of life



                         Light
Light is a most common aspect of our life. It's everywhere and surrounds us wherever we go. The light which may seem very simple and easy to us carries magnificent properties and extraordinary importance. Life is not possible without light and it is a source of knowledge for us. It contains phases of universe in it and it is scattered everywhere in the universe. It is present since the emergence of universe and it will last till the end of the universe. Sir Albert Einstein, a versatile genius got inspired to formulate various theories by light.
So let's discover more about the light......
 Introduction
Light is an electromagnetic wave which contains electric and magnetic components moving perpendicular to each other. This fact was first stated by sir Michael Faraday but he was unable to prove it mathematically rather it was proved by his young friend sir James Clark Maxwell. Light is obtained from various sources but the primary source of light is Sun and light takes 8 minutes  and 16.6 seconds to travel from sun to earth . It will ensure constant supply of light for billions of years. There are many other sources of light.
Light possess the fastest known speed i.e. 3*108 m/s in the universe. Light is an electromagnetic wave thus it doesn’t require any medium for it’s propagation in space. We are able to see any object only when the light coming from an object(can be it’s own or reflected) is received by our eyes.

Structure
Visible portion of electromagnetic spectrum which covers colours violet, indigo, blue, green, yellow, orange and red can easily be obtained by passing a beam of white light through a glass prism and is commonly observable in the form of rainbow.
                
Properties
Light shows many properties which leads to the emergence of various natural phenomena of light. These various properties of light are used in various instruments and are extremely helpful in describing a large arena of natural processes.

Some of it’s properties are listed below.....     
                                                                                            >>Reflection
                       



It is the process of bouncing back of light when it hits the surface of a body. This is due to the reflection of light that we can see non-luminous objects. The simplest example of this is mirror which reflects light coming from a body and forms a image of that body. A polished surface is a better reflector of light than a rough surface. 


>>Refraction
                       

The process of bending of light when it passes from one medium to another. It depends upon the density of two mediums. The speed of light changes resulting in the refraction of light. This is a very important property for optics as it directed the development of lenses and refracting telescopes. A pencil dipped in a glass of water when observed from outside appears to be broken due to this property. 

>>   Diffraction
                   
  It is the bending of light when it passes around the corners of an obstacle. The bending relies on the relative size of the wavelength of light to the size of the opening. The silver lining of some clouds is due to this property of light which occurs due to the diffraction of sunlight by water droplets present in the cloud.

>>   Total Internal reflection
                                    
It is the internal reflection of light when it strikes the boundary of the medium at an angle larger than the critical angle with respect to the normal to the surface. In this situation light can not pass through the medium rather it is reflected back. It can be observed on brightest water droplets. Optical fibers use this property of light.


>>Dispersion
                            

The process of splitting up of white light into it’s component colours when it passes through a transparent medium is called dispersion of light. When a white light passes through a glass prism a band of seven colours is obtained which consists of seven colours i.e. VIBGYOR.

Rainbow is formed by the dispersion of sunlight by rain drops present in the atmosphere.

>>   Interference
                            

The distribution of energy due to the disturbance of one wave by another wave when two light waves from different sources meet together is called interference of light. This modifies the distribution of energy in waves. There are two types of interference:-

a)Constructive interference

b)Destructive interference

Surface water waves show destructive interference and it can also be observed in radio waves. Rogue waves(ocean waves) show constructive interference.


>>   Polarization
                              

It is the property of a wave that it can oscillate with more than one orientation. Light exhibits polarization. It is very useful in the study of branches of science like optics, seismology, radio waves and micro waves.   

Nature of light
As stated by the wave theory and particle theory of light it has a dual nature. It behaves as a wave as well as a particle. At first light was treated only as a particle which successfully explained phenomena like reflection and refraction of light but it failed to explain the phenomena like interference and diffraction. Then wave theory of light came into effect(proposed by Huygens) which successfully explained interference and diffraction.

When we talk about the particle theory of light, the photon or quantum is taken as the particle of light.

Planck’s quantum theory of radiation
It was proposed in 1901 by sir Max Planck which forwarded that radiant energy (including light) is not emitted or absorbed continuously but discontinuously in the form of small packets of energy called quanta or photon. Energy carried by a quantum of radiation was given by formula:-   

                          E = hv                               Where h is planck’s constant(h = 6.626 * 10-34 j s) whereas v is frequency of light.

  
Speed of light
                         
  Speed of light is an universal constant which is denoted by c. It is the maximum speed known yet i.e.  3*108  m/s. It is enormously fast then also it takes some time to reach Earth from various stars. It may also take years to travel from a star to the Earth. The distance covered by light in one year is called a light year which is a unit of distance.

Suppose our sun is switched off or it is taken off from its place then what we are going to observe for next  8 minutes, the answer is that we will be totally unaware of this for next 8 minutes because light takes nearly 8 minutes to reach Earth from the Sun and in this period we will be continuously receiving light of sun that was emitted by it before its departure. Similarly when we stare at the sky then we are watching some of the stars those were dead long time back. 

Various phenomena of light
 Rainbows
                                                


 Afterglow


Airglow
                              


Alpenglow
                 
           

Belt of Venus
                           


Auroral light
                      


Green flash
                       


Light pillar
                     


Mirages
                            


Tyndall effect
                           


Sun dogs etc.
                  


Bioluminescence
It is the production and emission of light by a living organism. It is found in microorganisms, vertebrates, invertebrates and other living organisms. They contain a enzyme called luciferase and a pigment luciferin. Some of the bioluminescent organisms are-

a)Fireflies

b)Glow worms

c)Millipedes(motyxia)

d)Annelids

e)Mollusc

f)Anglerfish

g)Catshark

i)Flashlight fish

j)Lanterfish

k)Protists

l)Fungi(Panellus stipticus, Omphalotus olearius, Collybia tuberosa)
          
# Thank you #
image source -google.com

Sunday, 29 November 2015

Black holes

              Exploring black holes....
we are living in a world where there is always something to learn and our learning must not be confined to the boundaries of earth. In outer space there are various systems, bodies and processes to know about....It's interesting to know that space is not really  what it seems from the earth.Here is something about black holes to make you more familiar with them...
structure of a blackhole
Black holes
Black holes are regions in space-time where the gravitational force is so strong that even no electromagnetic radiation including light can not escape. In other words we can say these are regions where time and space are twisted too  much. The existence of black holes was first predicted by sir Einstien's theory of general relativity published in 1915.
Structure
Modern physics don't have much information about the structure of a black hole cause laws of physics do not work inside the boundaries of black hole due to it's very high gravitational force.These are some of the parts of a black hole.
1》Singularity÷ This is the point where all the mass of black hole is compressed. This point has zero volume and infinite density.
2》Event horizon÷ This is the boundary of a black hole from where even can not escape.
3》Schwarzschild radius÷ This is the radius of event horizon.  R = 2GM/c square 
Formation
Black holes are formed in various ways but generally they are formed by dying star which is very big in size. Size plays a crucial role in the formation of black hole. When a big star is in it's last stage it explodes with a supernova explosion and expells out it's outer parts in space and it's core is left behind. Then the gravitational force of star compresses the core causing it to collapse under it's own weight. The mass of core is collasped into a point called singularity which later acts as the center of black hole.
Types of black hole
According to the theory of general relativity there are three types black hole.
1)Stellar÷ These are formed when a massive star dies and collapses under its own wieght.e.g. Cygnus X-1 discovered in 1965.
2)Supermassive÷ These are very heavy and have mass equivalent to billions of suns. These are generally found in the centres of most galaxies, one bieng present at the centre of our own galxy named Sagittarius A.
3)Miniature÷ No miniature black hole has been discovered yet but scientists propose that these were formed during the early days of universe.
Growth
As the black holes aquire more and more matter from the sorrounding they continue to grow in size. Black hole may also merge with stars and black hole to grow larger.

Curious questions and thier and answers.......
1》Why massive stars form black hole at the end of their of  life?
Ans: During the normal lifespan of the star it tries to maintain the balance between gravity and pressure both of which work opposite to each other as the gravity pulls things inward while the pressure pushes outward. The pressure required to balance gravity comes from the nucler reactions going inside the core of star. Throughout it's whole life it is stable, but when it's nuclear fuel is exhausted then pressure is overthrown by gravity. As a result the core is compressed to form a black hole. Due to the very big size of core the electron-electron repulsions within the star can not balance very powerful gravity.

2》Why don't small stars form black hole?
Ans:This type of star is called 'white dwarf'. When stars are no more left with nuclear fuel to balance its gravitational force then the electron- electron repulsions inside the star create pressure required balance the gravitational force. Thus, the slowly cools down and vanished in the darkness of space.

3》What will happen if our sun turns into a black hole?
Ans:First of all it is not possible at all cause the size of the sun is very small to form a black hole. If we suppose then also the planets revolving around the sun are not going to be affected and they will continue to revolve in their orbits. They will need to be close enough (nearly 6-7 miles from the center of black hole) to get affected by it.
4》What interesting thing  is revealed about spinning black holes?
Ans:This kind of blackhole is also called charged black hole. This is hypothetically possible that the other end of this black hole opens into another spacetime which possibly may support time travel.
   
                                                                   ☆ Thank you ☆
                 If you have any queries or suggestions please leave a comment.

Monday, 26 October 2015

some interesting facts of science.......

science is a big chamber full of interesting things,explanations,experiments and facts that really blow mind........these facts force us to again think over the things we know...so here is a list of some of the facts of science.......
1》Plasma, the fourth state of matter due which sun and the stars glow...but you can easily find it...fluorescent tubes consists of plasma .
2》Work is a scalar quantity which has negative value.
3》Shake is a unit of time which equals to 10 to the power -8 seconds.
4》We know that electron is a particle...but it is a wave too.
5》At 0.01 degree celcius, all three phases of water exist simultneously.
6》You can float iron needle on water.
7》It takes only 8 minutes 20 sec. for sunlight to reach from sun to earth but it takes nearly 30,000 years to reach from core of the sun to its surface.
8》universe, so vast and unending....before Big-bang nearly 13.7 billion years ago was smaller than an atom.
9》Do  you know what is there at the centre of our milky way galaxy....there is a supermassive black hole at the center of our of galaxy having a mass equivalent to billions of suns.
10》There is a particle which has momentum but no mass...i.e. photon or quantum, the particle of light.
11》If you could travel at the speed of light...you will never experience the passage of time.
12》Light has no mass even then it is attracted by gravitational force of stars.
13》Sir Michael Faraday was first to state that light is an electromagnetic wave but he couldn't prove it mathematically.
14》Do you know with which organism life began on earth?...Life on earth began with a simle microscopic bacteria called cyanobacteria.
15》When it rained for the first time on  earth, it lasted for millions of years...forming gigantic oceans.
16》Gravitational force is the weakest force operating in nature, but that doesn't seem to be...it is responsible for keeping various planets and stars together.
17》What we observe is not always true...for instance when a coolie travels on a platform with a load on his head, work done by the coolie is zero...isn't that interesting?
18》Temperature lower than -273.15 degrees celcius is not possible.
19》H2 + O2 = H2O
this reaction is used for providing fuel to rocket...as oxygen and hydrogen gases are mixed to form water...and this is an highly exothermic reaction so a lot of energy is released which is used as a fuel for rocket.
20》we are a direct product of Einstein's equation E=mc2.
            ☆Thank you
I hope this will help you.