By : SHUBHAM GOTHWAL B-Tech (III) Computer Engineering What is the Big- Bang Theory? 1. ACCORDING TO BIG-BANG THEORY THE UNIVERSE WAS CREATED SOMETIME BETWEEN 10 BILLION AND 20 BILLION YEARS AGO FROM A COSMIC EXPLOSION THAT HURLED MATTER IN ALL DIRECTIONS. 2. PRESENT AGE OF UNIVERSE AS ESTIMATED IS BY. Now howll it DIE ? Expected death Universe will keep on expanding by the force of Dark Energy becoming colder & colder till temperature reaches absolute zero.(Dark Energy Wins) (Lonely In The Cosmos) My opinion Complete collapse of universe in singularity waving the way for a new Big-Bang.(Gravity dominates) One more Theory :-p Breaking down of stars, galaxies atoms and sub-atomic particles due to expansion of universe. Matter will get ripped apart.(Dark Energy Dominates) This was about the fate of our lovely Universe. Now, lets shift over to different events and objects present in the Universe Supernova Burst One of the most energetic explosive events known is a supernova. These occur at the end of a star's lifetime, when its nuclear fuel is exhausted and it is no longer supported by the release of nuclear energy. If the star is particularly massive, then its core will collapse and in so doing will release a huge amount of energy. This will cause a blast wave that ejects the star's envelope into interstellar space. A star can go supernova in one of two ways: I. Type I supernova: star accumulates matter from a nearby neighbor until a runaway nuclear reaction ignites. II. Type II supernova: star runs out of nuclear fuel and collapses under its own gravity. Red Giant A red giant star is a dying star in the last stages of stellar evolution. In only a few billion years, our own sun will turn into a red giant star, expand and engulf the inner planets, possibly even Earth. Most of the stars in the universe are main sequence stars those converting hydrogen into helium via nuclear fusion. A main sequence star may have a mass between a third to eight times that of the sun and eventually burn through the hydrogen in its core. Over its life, the outward pressure of fusion has balanced against the inward pressure of gravity. Once the fusion stops, gravity takes the lead and compresses the star smaller and tighter.main sequence starsnuclear fusion Red Giant Cont Temperatures increase with the contraction, eventually reaching levels where helium is able to fuse into carbon. Depending on the mass of the star, the helium burning might be gradual or might begin with an explosive flash. The energy produced by the helium fusion causes the star to expand outward to many times its original size.expand outward If stars have even lesser mass than our sun, they form RED DWARF. They never reach to the state of red giant. But it takes billions of year for a red dwarf to burn its fuel and turn into a WHITE DWARF. Pulsars Pulsars are types of neutron stars; the dead relics of massive stars. What sets pulsars apart from regular neutron stars is that theyre highly magnetized, and rotating at enormous speeds. Astronomers detect them by the radio pulses they emit at regular intervals. For stars between 1.4 and 3.2 times the mass of the Sun, they may still become supernovae, but they just dont have enough mass to make a black hole. These medium mass objects end their lives as neutron stars, and some of these can become pulsars or magnetars. When these stars collapse, they maintain their angular momentum. Black-Hole Much like a black body in thermodynamics, a black hole is a region of space that pulls everything and prevents anything from escaping, even light. The reason it is called a black hole is because it sucks up all the light that hits its border and reflects nothing. Formed when an amply compact mass deforms space and time, a black hole has a defined surface known as the event horizon which marks the point of no return. Few Facts About Black-Hole: 1. They affect time. 2. Stay away from event horizon. 3. There is a super-massive black hole at the center of our galaxy. 4. Black holes arent only destructive. 5. They are not necessarily black. 6. They are extremely dense. 7. The laws of physics break down at the center of the black hole Worm Hole A wormhole (also known as Einstein-Rosen Bridge) is a kind of shortcut through Space-time. They are predicted in General theory of relativity. Wormholes contain two mouths, with a throat connecting the two. The mouths would most likely be spheroidal and the throat is mostly straight stretch. If you want to pick up that shortcut, you will need a lot of negative energy to open its mouth. In short Schrodingers Thought Experiment The Principle of Superposition The Copenhagen Interpretation The Youngs Double Slit Experiment Some obvious questions Many Worlds Interpretation Implications for Artificial Intelligence The Thought Experiment o A steel chamber The Thought Experiment (Cont.) o A cat is placed in it The Thought Experiment (Cont.) o And with it, a small amount of a radioactive substance The Thought Experiment (Cont.) o And a veil of poison o The box is shielded against quantum decoherence The Thought Experiment (Cont.) o The cat can be alive The Thought Experiment (Cont.) o The cat can be dead The Thought Experiment (Cont.) o Or both? The Thought Experiment (Cont.) o Or both? Yes How? Any atom in the radioactive substance decays The veil breaks open and releases Poison The cat dies How? No atom in the radioactive substance decays The poison is not released The cat is alive How? Atom in the radioactive substance is in a state of both decayed and undecayed The cat is both dead and alive The principle of superposition The principle of superposition says that if an object can be in any configuration, and if the object could also be in another configuration, then the object can also be in a state which is a superposition of the two. The thought experiment uses this and transforms an indeterminacy in the atomic domain to macroscopic indeterminacy. The problem Thus an atom of the radioactive substance can be in both decayed and non-decayed states at the same time. This leads to the conclusion that the cat can be both dead and alive at the same time. But we can never observe the cat to be both dead and alive at the same time!!! The Youngs Double Slit Experiment Consider the equipment given below : The Youngs Double Slit Experiment The photon gun emits photons that reach the detector through the slit in the screen. The Youngs Double Slit Experiment With a single slit : Particle behaviour The Youngs Double Slit Experiment With 2 slits : Expected behaviour The Youngs Double Slit Experiment With 2 slits : Expected behaviour The Youngs Double Slit Experiment With 2 slits : Observed behaviour The Youngs Double Slit Experiment Inference: The photons are exhibiting both particle and wave nature resulting in interference Hence the pattern the interference pattern. So far so good The Youngs Double Slit Experiment The gun is slowed down to emit a single photon. Do you expect interference to happen now? The Youngs Double Slit Experiment Interference occurs even with a single photon Trying to get clever How can a photon interfere with itself ? With an aim to test from which slit the photon is actually passing to reach the other side, we place a monitor near one of the slits and redo the experiment with single photon. What do you expect now? Any guesses? The Youngs Double Slit Experiment The photon now behaves as a particle! The wave function of the photon has collapsed!!! Some obvious questions What does observation mean? Does observation need human interference? If yes, WHY? If no, then why does the wave function not collapse when the detector is inside the steel chamber? Energy Conservation Validity Check Using Thermodynamics Validity of Energy Conservation In the diagram, we have considered this universe as a system expanding from one side and compressing from other. Applying first law of thermodynamics, we get E = q + w E = q + P ext (V 2 V 1 ) (1) Also, E = q + P ext (V O + V 1 V 2 V O ).. (2) Equating (1) and (2), q + P ext (V 2 V 1 ) = q + P ext (V 1 V2) i.e. E = E Or 2 E = 0 Therefore, E = 0 This means that energy of this universe is constant. Thank You