outer world

       Newton showed us that gravity is an attractive force that keeps every celestial object in the universe under it's grip. ie., F=Gm1m2/r².The more the massive an object, the greater is the force of it's pull. A stone thrown up in the air comes back to earth due to its gravitational pull . The earth and moon attract each other. If mass of earth is mass 1 and that of moon is say mass 2 then the gravitational force between this two is directly proportional to the product of masses( mass 1× mass 2 ) and further this gravitational force between this two decreases as the distance between them increases. This is the reason why we see low ocean tides during full moon day. The interesting thing about gravity is that the pull of the gravitational force is a universal constant ie     6.67408×10^-11m³ kg^-1 s^-2.          Newton invented the equations which could be used to find the orbits of the planets in solar system and fire rockets. Assume that you are travelling in a spaceshi

     Quantum mechanics is not a completely understood theory as per scientific standards. There are some paradoxes yet to be accounted for. One of them was qua ntum entan glement . " When two parti cles say for example an electron pair when separated after being toget her, continue to remain entan gled even after the sepa ration of them by a large distances". It is like you and your roommate friend are separated from each other after being together for a long time, say by a distance of 100 kilometers, so sitting in your room, when you raise your left hand, your partner raises his right hand. But the question is how can a information travel faster than speed of light which was a big mystery? But later when we visit Eins teins lege ndary theory of relativity we find that nothing can go faster than speed of light.          To make it still more clearer let us take an thought example of a photon(massless light particle) which travels at the speed of light and split each photon

        Twenty years ago, scientists believed that the expansion of universe was due to momentum obtained during the Big bang. Scientists believed that due to gravity expansion will eventually slow down. According to the physics law the expansion of universe should slow down. But as years passes, the slowing was not observed.              In 1998, when the Hubble space Teles cope was launched which observed a very distant supernovae and were surprised that expansion of universe had not slowed due to gravity, instead it was accelerating.          It is estimated that expansion rate of universe is about 72 kilometers per second per mega parsec and this is called " Hubble constant". We can determine the present rate of expansion by measuring the velocities at which other Galaxies are moving away from us, using the Doppler effect.            The total mass-energy of the universe according to standard model of cosmology contains 4.9% of ordinary matter, 26.8% of dark matter

In 1928, Paul Dirac , a British physicist found an equation which could have two solutions, one for an electron with positive energy and another electron with an negative energy. But according to classical physics the energy of a particle must always be a positive number.         Dirac actually meant was that for every particle in nature there should exist an antiparticle or antimatter. As just we can find an real proof example in case of equation x²=4, which has two solutions +2 and -2. Same way for every matter there should exist antimatter. Matter and antimatter are exactly same having same mass but with opposite spin. As such case of electron a negative charged particle there should be a positive charged electron ie., antielectron (positron).           But when matter and antimatter come in contact produces an tremendous amount of energy in the form of gamma rays. It means that when they both come to contact due to oppositely charged, they both gets disappeared giving out treme

                    General relativity Gen eral relativity theory tells us about how the gravity works in the macro-universe. It mainly tells us how the planets orbit stars and how these stars and planets orbit the Galaxy and so on.                   Qua ntum Mechanics Quan tum Mechanics tells us about the mi cro-universe. It gives us descr iption of atoms, electrons and other sub-atomic particles and how they all interact with each other.                    Sci entists were trying to merge these two theories for a long time to make it is a unified theory due to some problems where these two theories don't agree with each other in principle. For example if we take black holes , which are extremely dense and are tiny forming singularity. So  which theory could be used to define among both the theories. Because relativity theory explains the extreme mass of black hole and quantum mechanics explains the singularity of black hole.         String theory says that the basic cons

            Since time is a hot topic today that runs across many theories in physics such as Newton's classi cal phy sics ,Quantum Mechanics, Relati vity, String theory etc, is the concept of time.          Time is used to define the speed of a moving objects in a classical sense and measure the gap between the two events. In the classical world , time always moves forward, and they are absolute, that is time is same for everyone. We all age with time and it is a witness to our ageing.       But in relativity physics time is not independent. Time is always related to space-time. Your time is determined based on where are you in space time. And time depends on your speed. Hence time ticks slow as you move faster. Finally when you reach the speed of light, time freezes. Assume that you have a time machine that could take you on a  space ride at the speed of light for 20 years and bring back home. When you meet your friends they would have  aged 20 years while you would still be