Black Holes, Wormholes & Time Machines free download online
Title: Black Holes, Wormholes & Time Machines Author(s): Jim Al-Khalili Pages: 288 Publisher: Taylor & Francis Publication date: 1999 Language: English Format: PDF ISBN-10: 0750305606 ISBN-13: Description: Time is a persistent theme in Jim Al-Khalili's account of modern physics. The book is based on a series of lectures that he gave to schoolchildren for the Institute of Physics, although it is also intended for adults. It aims to explain topics such as quantum mechanics, relativity, the big bang and black holes in a way that is accessible to the non-specialist.
Mr Al-Khalili explains that time is thought to have started along with the universe in the big bang, about 15 billion years ago (for comparison, the sun is about halfway through its life of about 10 billion years). Time also has a direction: although most physical processes are reversible, there is roughly speaking a tendency (familiar to parents) for the world to become ever less organised.
However, time does not always flow at the same rate: travelling close to the speed of light or falling into a black hole slows the passage of time relative to an observer. These are complex ideas that physicists usually express in mathematical language. Mr Al-Khalili avoids mathematics, yet gives an admirably clear account of some of the concepts involved.
The Physicist, October 1999
Jim Al-Khalili has written a splendid popular book. It begins where it must, with geometry, curved space and all that. The book is authoritative and yet reasonably simple. It contains some excellent insights and analogies, but always warns you of the limits to the analogies.
The book would be an excellent resource for school teachers in both Maths and Physics to enrich their teaching, and to enthuse their students. I especially liked the story of the hotel with an infinity of rooms, and the procedures for accommodating further infinities of guests. Finally the book delves into time and time travel and the debate on whether time travel is theoretically possible. This brings into focus the contradictions between quantum physics and general relativity. The reader is left well aware of what we do know and most importantly, what we don't know, and the exciting theoretical challenges ahead.
Many physicists will enjoy this easy to read book, but they will have to be patient with many of the easy bits. I highly recommend it for teenagers with an interest in science and for non-scientists interested in the deep questions of our universe.
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Title: Black Holes, Wormholes & Time Machines