ronaldweinland.info - KAALAM - stephen hawking books in tamil A Brief History of Time : From Big Bang to Black Holes . See and discover other items: history book. A Brief History of Time: From the Big Bang to Black Holes is a popular-science book on cosmology by British physicist Stephen Hawking. It was first published in . Stephen Hawking, one of the most brilliant theoretical physicists in history, wrote the modern classic A Brief History of Time to help non-scientists understand.
|Language:||English, Spanish, French|
|Genre:||Children & Youth|
|ePub File Size:||27.35 MB|
|PDF File Size:||18.57 MB|
|Distribution:||Free* [*Register to download]|
I didn't write a foreword to the original edition of A Brief History of Time. A brief history of time/A Brief History in ronaldweinland.info (1 of 2) [2/20/ A film about the life and work of the cosmologist, Stephen Hawking, who despite his near total paralysis, is one of the great minds of all time. The Worlds First Time Machine (Science Documentary) The Life of Stephen Hawking - Doc Film (R.I.P.). A Brief History Of Time by Stephen HawkingHawking attempts to explain a range of subjects in cosmology, including the Big Bang, black holes.
How did the universe begin—and what made its start possible? Does time always flow forward? Is the universe unending—or are there boundaries? Are there other dimensions in space? What will happen when it all ends? With exciting images and profound imagination, Stephen Hawking brings us closer to the ultimate secrets at the very heart of creation. His is a brain of extraordinary power.
Four distinct phases of globalisation can be discerned in modern history. The first phase began in the sixteenth century with the passing of pre-modern localism, improvements in maritime technology leading to the great age of maritime exploration, discovery and mercantilism, the European Renaissance, centralising tendencies associated with absolute monarchy and the emergence of modern nation states following the Peace of Westphalia of , and the spread of the ideals of the American and French Revolutions from the eighteenth century.
The second phase from the late eighteenth century was marked by the spread of the Industrial Revolution and vast improvements in human technology, inanimate traction, productivity and demand, which led to mass production and conveyance of merchandise goods and people, cross-border integration through bulk long-distance trade, colonial plunder, investment flows and empire during a phase of European imperial expansion which saw the flag follow trade across the globe.
The Industrial Revolution opened up a rapidly widening income gap between Europe and America on the one hand, and the rest of the world on the other. Even as trade and flags disengaged, the per capita income between developed countries and the erstwhile colonies continued to diverge.
During the third phase, merchandise trade resumed its triumphant march as the engine of hyper growth in East Asia from the s.
But whereas the globalisation thrust in the second phase in the nineteenth century involved, in the main, the export of mass-produced merchandise to the colonies, this time round the export dynamism came from the erstwhile colonies. This globalisation thrust was led by trans national corporations TNCs that endeavoured to disseminate international trade and modern technology to every flag on earth.
They can be found when black holes suck in other stars. When black holes suck in other stars, the black hole lets out X-rays , which can be seen by telescopes. In this chapter, Hawking talks about his bet with another scientist, Kip Thorne.
Hawking bet that black holes did not exist, because he did not want his work on black holes to be wasted. He lost the bet. Hawking realized that the event horizon of a black hole could only get bigger, not smaller. The area of the event horizon of a black hole gets bigger whenever something falls into the black hole.
He also realized that when two black holes combine, the size of the new event horizon is greater than or equal to the sum of the event horizons of the two original black holes. This means that a black hole's event horizon can never get smaller.
Disorder, also known as entropy , is related to black holes. There is a scientific law that has to do with entropy.
This law is called the second law of thermodynamics , and it says that entropy or disorder will always increase in an isolated system for example, the universe. The relation between the amount of entropy in a black hole and the size of the black hole's event horizon was first thought of by a research student Jacob Bekenstein and proven by Hawking, whose calculations said that black holes emit radiation.
This was strange, because it was already said that nothing can escape from a black hole's event horizon. This problem was solved when the idea of pairs of "virtual particles" was thought of. One of the pair of particles would fall into the black hole, and the other would escape.
This would look like the black hole was emitting particles. This idea seemed strange at first, but many people accepted it after a while. Chapter 8: The Origin and Fate of the Universe[ edit ] The Big Bang and the evolution of the universe How the universe started and how it might end is discussed in this chapter. Most scientists agree that the universe started in an expansion called the Big Bang. The model for this is called the "hot big bang model".
When the universe starts getting bigger, the things inside of it also begin to get cooler. When the universe was first beginning, it was infinitely hot. The temperature of the universe cooled and the things inside the universe began to clump together. Hawking also discusses how the universe could have been.
For example, if the universe formed and then collapsed quickly, there would not be enough time for life to form. Another example would be a universe that expanded too quickly. If a universe expanded too quickly, it would become almost empty.
The idea of many universes is called the many-worlds interpretation.
Inflationary models and the idea of a theory that unifies quantum mechanics and gravity also are discussed in this chapter. Each particle has many histories. This idea is known as Feynman's theory of sum over histories. A theory that unifies quantum mechanics and gravity should have Feynman's theory in it. To find the chance that a particle will pass through a point, the waves of each particle needs to be added up. These waves happen in imaginary time.
Imaginary numbers, when multiplied by themselves, make a negative number. Chapter 9: The Arrow of Time[ edit ] In this chapter Hawking talks about why "real time" as humans observe and experience it in contrast to the "imaginary time" in the laws of science seems to have a certain direction, notably from the past towards the future.
The things that give time this property are the arrows of time. Firstly, there is the thermodynamic arrow of time. According to this, starting from any higher order organized state, the overall disorderliness in the world always increases as time passes.
This is why we never see the broken pieces of a cup gather themselves together to form a whole cup. Even though human civilizations have tried to make things more orderly, the energy dissipated in this process has created more overall disorder in the universe.
The second arrow is the psychological arrow of time. Our subjective sense of time seems to flow in one direction, which is why we remember the past and not the future. Hawking claims that our brain measures time in a way where disorder increases in the direction of time.
We never observe it working in the opposite direction. In other words, the psychological arrow of time is intertwined with the thermodynamic arrow of time.
Thirdly there is the cosmological arrow of time, the direction of time in which our universe is expanding and not contracting. Hawking believes that in order for us to observe and experience the first two arrows of time, the universe would have to begin in a very smooth and orderly state. And then as it expanded, it became more disorderly. So the thermodynamic arrow agrees with the cosmological arrow.
Because of the "no boundary" proposal for the universe, after a period of expansion, the universe will probably start to contract.
It will probably not go backwards in time to a more smooth, orderly state. The thermodynamic arrow in the contracting phase will not be as strong. As for why humans experience these three arrows of time going in the same direction, Hawking postulates that humans have been living in the expanding phase of the universe. He thinks that intelligent life couldn't exist in the contracting phase of the universe.
Only the expanding phase of the universe is suitable for intelligent beings like humans to exist, because it contains a strong thermodynamic arrow.
Hawking calls this the "weak anthropic principle". Chapter The Unification of Physics[ edit ] The fundamental objects of string theory are open and closed strings. Physicists have come up with partial theories to describe a limited range of things, but a complete, unified and consistent theory which can take into account all of these partial theories remain unknown.
Hawking is cautiously optimistic that such a unified theory of the universe may be found soon. Such a theory must combine the classical theory of gravity with the uncertainty principle found in quantum mechanics. Attempts to do that have led to the occurrence of absurd infinitely massed particles or an infinitely small universe. In , the theory of "supergravity" was suggested as a solution.
But the calculations to verify the theory was deemed time-consuming and thus abandoned. In , another set of theories called the "string theories", where basic objects are not particles but two-dimensional strings, became popular among physicists. They were claimed to explain the existence of certain particles better than supergravity and other theories.
However, according to string theories, instead of the usual four space-time dimensions, the universe could have dozens of them.
It is imagined that humans do not experience the other dimensions because these are too tightly curled up. This is due to the "weak anthropic principle", according to which intelligent beings like humans cannot exist in any other way. String theories appear to allow this situation for certain regions of the universe, but there may be other regions of the universe where more than four dimensions are prominent.
Furthermore, supergravity, p-brane and string theories all describe different situations with similar results, as if using different approximations of the same theory. Hawking thus proposes three possibilities: 1 there exists a complete unified theory that we will eventually find; 2 there are an infinite number of theories that overlap and describe the universe more and more accurately and 3 there is no ultimate theory. The third possibility has been sidestepped by acknowledging the limits set by the uncertainty principle.
The second possibility describes what has been happening in physical sciences so far, with increasingly accurate partial theories. Hawking believes that such refinement has a limit and that by studying the very early stages of the universe in a laboratory setting, it is possible to finally find a complete unified theory in the 21st century.
Such a theory might not be proven but would be mathematically consistent. The predictions of such a basic set of laws would match our observations. However, given the complicated nature of realistic situations, it would only be a first step to a complete understanding of the events around us. Chapter Conclusion[ edit ] Humans have always wanted to make sense of the universe and their place in it. At first, events were considered random and controlled by human-like emotional spirits.
But in astronomy and in some other situations, regularities were observed.
With the advancement of the human civilization in the modern age, more regularities and laws were discovered. Laplace suggested at the beginning of the nineteenth century that the universe's structure and evolution could eventually be precisely explained by a set of laws. However, the origin of these laws was left in God's domain. In the twentieth century, quantum theory introduced the uncertainty principle, which set limits to the predictive accuracy of laws to be discovered.
The big bang implied by the general theory of relativity indicates that a creator of the universe or God has the freedom to choose the origin and the laws of the universe.
When one combines theory of relativity with quantum mechanics, however, a unified and completely self-contained theory may emerge, in which God has little or no role to play.
Dispatched from the UK in 2 business days When will my order arrive? Home Contact us Help Free delivery worldwide. Free delivery worldwide. Bestselling Series. Harry Potter. Popular Features. New in A Brief History Of Time: