Hawking's book is the most understandable description of the physics of time and matter that I've encountered. Not a text book on physics - it's an explanation of classical relativity and quantum mechanics for laymen that focuses on the origin and future of the universe. It describes what scientists have discovered so far and how their thinking has changed over time, and then discusses the possible futures that seem to be implied. ( )

The science gets a little deep in places, so this book might not been for the feint of heart, but nevertheless a great read if you're interested in physics and the nature of time.

The illustrated edition is liberally illustrated with many beautiful diagrams and illustrations, which for the most part don't aid in understanding the material, but definitely increase one's overall enjoyment of the book. Well worth the extra cost. ( )

HISTORIA DEL TIEMPO

Mi primera exposición a "A Brief History of Time" fue cintas de audio narradas por Michael Jackson, no el cantante, sino un inglés con un hermoso acento inglés. La clara redacción que fluía tan fácilmente me hizo pensar que las cintas contenían una nueva redacción especial del libro. Descubrir que las palabras en las cintas eran idénticas a las del libro me sorprendió.

Esta nueva versión ilustrada agrega hermosos diagramas y fotografías que hacen que el libro de Hawkin sea más fácil de entender. Los lectores de adolescentes podrán seguir las principales líneas de razonamiento en este libro. Hawkin no entra en las matemáticas y los detalles minuciosos. Presenta una historia de teorías sobre el universo y qué descubrimientos impulsaron el refinamiento de las teorías existentes o el desarrollo de nuevas teorías. Hawkin organiza su libro para describir cómo los astrónomos modernos entienden el tiempo. Al igual que la longitud, la anchura y el ancho, el tiempo es la cuarta dimensión del universo.

El universo comenzó cuando toda la materia en el universo explotó en una cantidad infinitamente pequeña de espacio: el "Big Bang". Antes del Big Bang, el tiempo no existía; de ahí el título "Una breve historia del tiempo". Hawkin describe cómo comenzó el tiempo cuando el universo comenzó y cómo el universo ha cambiado con el tiempo. Los científicos creen que el universo se ha estado expandiendo desde el Big Bang. Hawkin también describe las proyecciones actuales de lo que sucederá en el futuro. ¿El universo continuará expandiéndose? ¿Dejará de expandirse y encontrará un tamaño fijo? ¿Cambiará de dirección y comenzará un largo colapso que hará que toda la materia se condense en un espacio infinitamente pequeño: la "gran crisis"?

El encantador sentido del humor de Stephen Hawkin mejora enormemente su excelente descripción del pensamiento científico. Disfruté mucho leyendo este libro.

Lavishly if haphazardly illustrated. About half the illustrations are historical and about half are diagrams intended to illustrate the concepts presented.

1. Our Picture of the Universe
An overview of well-known early cosmology. Aristotle convinced the earth is round, Ptolemy, Copernicus, Kepler, Galileo, Newton. If the universe is infinite and static it must (a) collapse under the force of gravity, and (b) be really bright all the time since the light from all the stars in its infinity must reach the earth. When Edwin Hubble discovered that the galaxies were in general receding from us and each other many scientists inferred the "big bang". Brief mention of the orbit of Mercury and Einstein. Relativity and quantum mechanics are somehow incompatible. Hard to justify the search for a unified theory of everything on practical grounds.

2. Space and Time

My first exposure to "A Brief History of Time" was audio tapes narrated by Michael Jackson, not the singer, but an Englishman with a beautiful English accent. The clear wording that flowed so easily made me think the tapes contained a special rewording of the book. Discovering that the words on the tapes were identical with those in the book surprised me.

This new illustrated version adds beautiful diagrams and photographs that make Hawkin's easily understood book even more easily understood. Teen-age readers will be able to follow the main lines of reasoning in this book. Hawkin does not get into math and minute detail. He presents a history of theories about the universe and what discoveries prompted refinement of existing theories or development of new theories. Hawkin organizes his book to describe how modern astronomers understand time. Like length, breadth, and width, time is the fourth dimension of the universe.

The universe began when all matter in the universe exploded out of an infinitely small amount of space: the "big bang." Before the big bang, time did not exist; hence, the title "A Brief History of Time." Hawkin describes how time started when the universe started and how the universe has changed with time. Scientists believe the universe has been expanding ever since the big bang. Hawkin also describes current projections of what will happen in the future. Will the universe continue to expand? Will it stop expanding and find a fixed size? Will it eventually reverse direction and begin a long collapse causing all matter to condense into an infinitely small space: the "big crunch?"

Stephen Hawkin's charming sense of humor greatly enhances his excellent description of scientific thought. I very much enjoyed reading this book. ( )