{"product_id":"a-briefer-history-of-time-isbn-9780553804362","title":"A Briefer History of Time","description":"\u003cp\u003e\u003cb\u003eFROM ONE OF THE MOST BRILLIANT MINDS OF OUR TIME COMES A BOOK THAT CLARIFIES HIS MOST IMPORTANT IDEAS\u003c\/b\u003e\u003cbr\u003e \u003cb\u003e \u003c\/b\u003e\u003cbr\u003e Stephen Hawking’s worldwide bestseller \u003ci\u003eA Brief History of Time\u003c\/i\u003e remains a landmark volume in scientific writing. But for readers who have asked for a more accessible formulation of its key concepts—the nature of space and time, the role of God in creation, and the history and future of the universe—\u003ci\u003eA Briefer History of Time\u003c\/i\u003e is Professor Hawking’s response.\u003cbr\u003e  \u003cbr\u003e Although “briefer,” this book is much more than a mere explanation of Hawking’s earlier work. \u003ci\u003eA Briefer History of Time\u003c\/i\u003e both clarifies and expands on the great subjects of the original, and records the latest developments in the field—from string theory to the search for a unified theory of all the forces of physics. Thirty-seven full-color illustrations enhance the text and make \u003ci\u003eA Briefer History of Time\u003c\/i\u003e an exhilarating and must-have addition in its own right to the great literature of science and ideas.\u003c\/p\u003e\u003cp\u003e\u003cb\u003ePraise for the original edition of \u003ci\u003eA Brief History of Time\u003c\/i\u003e\u003c\/b\u003e\u003cbr\u003e  \u003cbr\u003e “[Hawking] can explain the complexities of cosmological physics with an engaging combination of clarity and wit. . . . His is a brain of extraordinary power.”—\u003ci\u003eThe New York Review of Books\u003c\/i\u003e\u003cbr\u003e  \u003cbr\u003e “Lively and provocative . . . Mr. Hawking clearly possesses a natural teacher’s gifts—easy, good-natured humor and an ability to illustrate highly complex propositions with analogies plucked from daily life.”—\u003ci\u003eThe New York Times\u003c\/i\u003e\u003cbr\u003e  \u003cbr\u003e “Even as he sits helpless in his wheelchair, his mind seems to soar ever more brilliantly across the vastness of space and time to unlock the secrets of the universe.”—\u003ci\u003eTime\u003c\/i\u003e\u003cbr\u003e  \u003cbr\u003e “This book marries a child’s wonder to a genius’s intellect. We journey into Hawking’s universe while marvelling at his mind.”—\u003ci\u003eThe Sunday Times\u003c\/i\u003e (London)\u003cbr\u003e  \u003cbr\u003e “A masterful summary of what physicists now think the world is made of and how it got that way.”—\u003ci\u003eThe Wall Street Journal\u003c\/i\u003e\u003cbr\u003e  \u003cbr\u003e “Charming and lucid . . . [a book of] sunny brilliance.”—\u003ci\u003eThe New Yorker\u003c\/i\u003e\u003c\/p\u003e\u003cp\u003e\u003cb\u003eStephen Hawking\u003c\/b\u003e was the Lucasian Professor of Mathematics at the University of Cambridge for thirty years and the recipient of numerous awards and honors including the presidential Medal of Freedom. His books for the general reader include \u003ci\u003eMy Brief History,\u003c\/i\u003e the classic \u003ci\u003eA Brief History of Time,\u003c\/i\u003e the essay collection \u003ci\u003eBlack Holes and Baby Universes, The Universe in a Nutshell,\u003c\/i\u003e and, with Leonard Mlodinow, \u003ci\u003eA Briefer History of Time\u003c\/i\u003e and \u003ci\u003eThe Grand Design\u003c\/i\u003e. Stephen Hawking died in 2018.\u003cbr\u003e\u003cbr\u003e \u003cb\u003eLeonard Mlodinow\u003c\/b\u003e is a physicist and the author of \u003ci\u003eFeynman’s Rainbow, Euclid’s Window,\u003c\/i\u003e and \u003ci\u003eThe Drunkard’s Walk\u003c\/i\u003e. He lives in Pasadena, California.\u003c\/p\u003e\u003ci\u003eChapter One\u003cbr\u003e\u003cbr\u003e \u003cbr\u003e Thinking About the Universe   \u003cbr\u003e \u003c\/i\u003e\u003cbr\u003e We live in a stragne and wonderful  universe. Its age, size, violence, and beauty require extraordinary imagination to  appreciate. The place we humans hold within this vast cosmos can seem pretty insignificant.  And so we try to make sense of it all and to see how we fit in. Some decades ago,  a well-known scientist (some say it was Bertrand Russell) gave a public lecture on  astronomy. He described how the earth orbits around the sun and how the sun, in turn,  orbits around the center of a vast collection of stars called our galaxy. At the  end of the lecture, a little old lady at the back of the room got up and said: \"What  you have told us is rubbish. The world is really a flat plate supported on the back  of a giant turtle.\" The scientist gave a superior smile before replying, \"What is  the turtle standing on?\" \"You're very clever, young man, very clever,\" said the old  lady. \"But it's turtles all the way down!\"   \u003cbr\u003e\u003cbr\u003e Most people nowadays would find the  picture of our universe as an infinite tower of turtles rather ridiculous. But why  should we think we know better? Forget for a minute what you know-or think you know-about  space. Then gaze upward at the night sky. What would you make of all those points  of light? Are they tiny fires? It can be hard to imagine what they really are, for  what they really are is far beyond our ordinary experience. If you are a regular  stargazer, you have probably seen an elusive light hovering near the horizon at twilight.  It is a planet, Mercury, but it is nothing like our own planet. A day on Mercury  lasts for two-thirds of the planet's year. Its surface reaches temperatures of over  400 degrees Celsius when the sun is out, then falls to almost -200 degrees Celsius  in the dead of night. Yet as different as Mercury is from our own planet, it is not  nearly as hard to imagine as a typical star, which is a huge furnace that burns billions  of pounds of matter each second and reaches temperatures of tens of millions of degrees  at its core.   \u003cbr\u003e\u003cbr\u003e Another thing that is hard to imagine is how far away the planets  and stars really are. The ancient Chinese built stone towers so they could have a  closer look at the stars. It's natural to think the stars and planets are much closer  than they really are-after all, in everyday life we have no experience of the huge  distances of space. Those distances are so large that it doesn't even make sense  to measure them in feet or miles, the way we measure most lengths. Instead we use  the light-year, which is the distance light travels in a year. In one second, a beam  of light will travel 186,000 miles, so a light-year is a very long distance. The  nearest star, other than our sun, is called Proxima Centauri (also known as Alpha  Centauri C), which is about four light-years away. That is so far that even with  the fastest spaceship on the drawing boards today, a trip to it would take about  ten thousand years.   \u003cbr\u003e\u003cbr\u003e Ancient people tried hard to understand the universe, but  they hadn't yet developed our mathematics and science. Today we have powerful tools:  mental tools such as mathematics and the scientific method, and technological tools  like computers and telescopes. With the help of these tools, scientists have pieced  together a lot of knowledge about space. But what do we really know about the universe,  and how do we know it? Where did the universe come from? Where is it going? Did the  universe have a beginning, and if so, what happened before then? What is the nature  of time? Will it ever come to an end? Can we go backward in time? Recent breakthroughs  in physics, made possible in part by new technology, suggest answers to some of these  long-standing questions. Someday these answers may seem as obvious to us as the earth  orbiting the sun-or perhaps as ridiculous as a tower of turtles. Only time (whatever  that may be) will tell. \u003cbr\u003e\u003cbr\u003e\u003ci\u003eChapter Two\u003cbr\u003e\u003cbr\u003e\u003cbr\u003eOur Evolving Picture of the Universe \u003cbr\u003e\u003c\/i\u003e\u003cbr\u003eALTHOUGH AS LATE AS THE TIME of Christopher Columbus it was common to find people who thought the earth was flat (and you can even find a few such people today), we can trace the roots of modern astronomy back to the ancient Greeks. Around 340 B.C., the Greek philosopher Aristotle wrote a book called \u003ci\u003eOn the Heavens\u003c\/i\u003e. In that book, Aristotle made good arguments for believing that the earth was a sphere rather than flat like a plate. \u003cbr\u003e\u003cbr\u003eOne argument was based on eclipses of the moon. Aristotle realized that these eclipses were caused by the earth coming between the sun and the moon. When that happened, the earth would cast its shadow on the moon, causing the eclipse. Aristotle noticed that the earth's shadow was always round. This is what you would expect if the earth was a sphere, but not if it was a flat disk. If the earth were a flat disk, its shadow would be round only if the eclipse happened at a time when the sun was directly under the center of the disk. At other times the shadow would be elongated-in the shape of an ellipse (an ellipse is an elongated circle). \u003cbr\u003e\u003cbr\u003eThe Greeks had another argument for the earth being round. If the earth were flat, you would expect a ship approaching from the horizon to appear first as a tiny, featureless dot. Then, as it sailed closer, you would gradually be able to make out more detail, such as its sails and hull. But that is not what happens. When a ship appears on the horizon, the first things you see are the ship's sails. Only later do you see its hull. The fact that a ship's masts, rising high above the hull, are the first part of the ship to poke up over the horizon is evidence that the earth is a ball. \u003cbr\u003e\u003cbr\u003eThe Greeks also paid a lot of attention to the night sky. By Aristotle's time, people had for centuries been recording how the lights in the night sky moved. They noticed that although almost all of the thousands of lights they saw seemed to move together across the sky, five of them (not counting the moon) did not. They would sometimes wander off from a regular east-west path and then double back. These lights were named planets-the Greek word for \"wanderer.\" The Greeks observed only five planets because five are all we can see with the naked eye: Mercury, Venus, Mars, Jupiter, and Saturn. Today we know why the planets take such unusual paths across the sky: though the stars hardly move at all in comparison to our solar system, the planets orbit the sun, so their motion in the night sky is much more complicated than the motion of the distant stars. \u003cbr\u003e\u003cbr\u003eAristotle thought that the earth was stationary and that the sun, the moon, the planets, and the stars moved in circular orbits about the earth. He believed this because he felt, for mystical reasons, that the earth was the center of the universe and that circular motion was the most perfect. In the second century a.d. another Greek, Ptolemy, turned this idea into a complete model of the heavens. Ptolemy was passionate about his studies. \"When I follow at my pleasure the serried multitude of the stars in their circular course,\" he wrote, \"my feet no longer touch the earth.\" \u003cbr\u003e\u003cbr\u003eIn Ptolemy's model, eight rotating spheres surrounded the earth. Each sphere was successively larger than the one before it, something like a Russian nesting doll. The earth was at the center of the spheres. What lay beyond the last sphere was never made very clear, but it certainly was not part of mankind's observable universe. Thus the outermost sphere was a kind of boundary, or container, for the universe. The stars occupied fixed positions on that sphere, so when it rotated, the stars stayed in the same positions relative to each other and rotated together, as a group, across the sky, just as we observe. The inner spheres carried the planets. These were not fixed to their respective spheres as the stars were, but moved upon their spheres in small circles called epicycles. As the planetary spheres rotated and the planets themselves moved upon their spheres, the paths they took relative to the earth were complex ones. In this way, Ptolemy was able to account for the fact that the observed paths of the planets were much more complicated than simple circles across the sky. \u003cbr\u003e\u003cbr\u003ePtolemy's model provided a fairly accurate system for predicting the positions of heavenly bodies in the sky. But in order to predict these positions correctly, Ptolemy had to make an assumption that the moon followed a path that sometimes brought it twice as close to the earth as at other times. And that meant that the moon ought sometimes to appear twice as big as at other times! Ptolemy recognized this flaw, but nevertheless his model was generally, although not universally, accepted. It was adopted by the Christian church as the picture of the universe that was in accordance with scripture, for it had the great advantage that it left lots of room outside the sphere of fixed stars for heaven and hell.","brand":"Bantam","offers":[{"title":"Default Title","offer_id":46301227352293,"sku":"NP9780553804362","price":27.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1842\/7735\/files\/9780553804362.jpg?v=1767720322","url":"https:\/\/k12savings.com\/products\/a-briefer-history-of-time-isbn-9780553804362","provider":"K12savings","version":"1.0","type":"link"}