Messenger Like many students of my generation, Stephen Hawking had already had enormous influence on me long before we ever met. When I was hesitating about my A-level choices, it was his book A Brief History of Time that convinced me to continue with physical sciences. InHawking and mathematical physicist Roger Penrose gave a series of inspiring lectures about cosmology in Cambridge.
Publication[ edit ] Early inHawking first approached Simon Mittonthe editor in charge of astronomy books at Cambridge University Presswith his ideas for a popular book on cosmology. Mitton was doubtful about all the equations in the draft manuscript, which he felt would put off the buyers in airport bookshops that Hawking wished to reach.
With some difficulty, he persuaded Hawking to drop all but one equation. The book does employ a number of complex models, diagrams, and other illustrations to detail some of the concepts it explores.
Contents[ edit ] In A Brief History of Time, Stephen Hawking attempts to explain a range of subjects in cosmologyincluding the Big Bangblack holes and light conesto the nonspecialist reader.
His main goal is to give an overview of the subject, but he also attempts to explain some complex mathematics.
In the edition of the book and subsequent editions, Hawking discusses the possibility of time travel and wormholes and explores the possibility of having a universe without a quantum singularity at the beginning of time. Our Picture of the Universe[ edit ] A picture of Ptolemy's earth-centric model about the location of the planets, stars, and sun.
In the first chapter, Hawking discusses the history of astronomical studiesincluding the ideas of Aristotle and Ptolemy. Aristotle, unlike many other people of his time, thought that the Earth was round.
He came to this conclusion by observing lunar eclipseswhich he thought were caused by the earth's round shadow, and also by observing an increase in altitude of the North Star from the perspective of observers situated further to the north.
Aristotle also thought that the sun and stars went around the Earth in perfect circles, because of "mystical reasons". Second-century Greek astronomer Ptolemy also pondered the positions of the sun and stars in the universe and made a planetary model that described Aristotle's thinking in more detail.
Kepler's sun-centric elliptical orbit model of the solar system Today, it is known that the opposite is true: The Aristotelian and Ptolemaic ideas about the position of the stars and sun were disproved in The first person to present a detailed argument that the earth revolves around the sun was the Polish priest Nicholas Copernicusin Nearly a century later, Galileo Galileian Italian scientist, and Johannes Keplera German scientist, studied how the moons of some planets moved in the sky, and used their observations to validate Copernicus's thinking.
To fit the observations, Kepler proposed an elliptical orbit model instead of a circular one. In his book on gravity, Principia MathematicaIsaac Newton used complex mathematics to further support Copernicus's idea.
Newton's model also meant that stars, like the sun, were not fixed but, rather, faraway moving objects. Nevertheless, Newton believed that the universe was made up of an infinite number of stars which were more or less static. Many of his contemporaries, including German philosopher Heinrich Olbersdisagreed.
The origin of the universe represented another great topic of study and debate over the centuries. Early philosophers like Aristotle thought that the universe has existed forever, while theologians such as St. Augustine believed it was created at a specific time. Augustine also believed that time was a concept that was born with the creation of the universe.
More than years later, German philosopher Immanuel Kant thought that time goes back forever. Inastronomer Edwin Hubble discovered that galaxies are moving away from each other.
Consequently, there was a time, between ten and twenty billion years ago, when they were all together in one singular extremely dense place. This discovery brought the concept of the beginning of the universe within the province of science.
Today, scientists use two partial theories, Einstein's general theory of relativity and quantum mechanicsto describe the workings of the universe. Scientists are still looking for a complete unified theory that would describe everything in the universe.
Hawking believes that the discovery of a complete unified theory may not aid the survival of our species, and may not even affect our life-style, but that humanity's deepest desire for knowledge is justification enough for our continuing quest.
Space and Time[ edit ] Stephen Hawking talks about how the Aristotle theory of absolute space came to an end by the Newton's theory that 'rest' and 'motion' can be the same state if an observer sees the event at rest or if he moves with the same speed as that of the event.
So 'rest' can't be the standard position. Moreover, Galileo Galilei also disproves Aristotle theory that heavier body falls more quickly than the lighter one just because of its mass. He experimentally proves it by sliding objects of different weights, and even concludes that both these object would fall at same rate and would reach the bottom at the same time, unless external force acts on them."A Brief History of Time, published in , was a landmark volume in science writing and in world-wide acclaim and popularity, with more than 9 million copies in print globally.
Stephen Hawking's a Brief History of Time: A Reader's Companion was a time stoppingly good book.
It made me think on a higher level about the universe, black holes, and time. Much of this information, like the fact that black holes give off radiation, I had not yet begun to comprehend in the far reaches of my younge mind/5(7).
Download 1, free online courses from the world's top universities -- Stanford, Yale, MIT, & more. Over 40, hours of free audio & video lectures. The first point, which deals with the origin of life on Earth, is known as panspermia — literally, "seeds everywhere." Its earliest recorded advocate was the Greek .
Watch video · Follow the extraordinary life of Stephen Hawking on ashio-midori.com Learn more about his groundbreaking work in physics and cosmology, his popular science books and the effects of his affliction. For the first time, Stephen Hawking turns his gaze inward for a revealing look at his own life and intellectual evolution.
My Brief History recounts Stephen Hawking’s improbable journey, from his post-war London boyhood to his years of international acclaim and ashio-midori.comrated with rarely seen photographs, this concise, witty and candid .