Reverse Time Travel

by Barry Chapman

Reverse time travel is a real possibility, according to new theories based on established hypotheses such as Einstein's Special Theory of Relativity and Newton's Laws of Physics. Time dilation, higher dimensions, and much, much more are all explained in easy-to-understand layman's terms for the non-scientific reader. Perplexing formulas, black holes, the time-space continuum, worm holes, and entropy all makes sense when explained in plain language. "A great book for expanding your viewpoint of a growing universe."— The INFO Journal . 160 pages, 61 b/w illus., 6 1/4 X 9 1/4.

Genres: Science

160 pages, Paperback

First published January 1, 1995

Reviews

[Toastbrot123 · Rating 5 out of 5]

Found this in my university library while on the search for a book on relativity where I don't have to calculate 4x4 Minkovski matrices to understand relativity; and I was not disapointed. This book teaches the basic ideas of general relativity and some further crazy stuff about time travel while only needing Lorentz transformations and some simple math. The rest is conveyed in a bunch of thought experiments and sketches. And let me tell you: It gets the most fun when the author starts theorizing about passing the Schwartzchild radius of a black hole.

But here I am a bit confused by the low review score on this book: The only written review is a rather harsh 1 star review pointing out some percieved errors in the book and I'd like to use these paragraphs to counter these.

First is about the distance to Alpha Centauri: I checked the chapter and the author writes about Proxima Centauri. But this is irrelevant, both are roughly 4 Ly. away from the earth. The important point is that distance depends on the speed of the inertial system! A rocket traveling at nearly the speed of light experiences relativistic length contraction, so the distance might change to something like only 2.6 Ly. depending on the speed of the moving observers. Meaning that the distance from earth to Proxima Centauri is 4 Ly. for an observer at rest, but can become 2.6 Ly. for an observer traveling at very high speeds.

The second point is the confusion about the distinction between v and v'. Contrary to the believe of the 1 star reviewer this distinction is absolutely irrelvant! This might be a bit confusing to people not familiar with the topic, but in general relativity all inertial systems are equivalent. Meaning that it does not matter if inertial system v is moving or if inertial system v' is moving, it is all relative (thats why its called relativity theory).

tldr; book is good if you want to understand general relativity without getting a degree in physics (but from personal experience i can tell: the degree helps)

[Tony Calder · Rating 1 out of 5]

I have marked this book as read, although I haven't finished it. But I will not be finishing it. I tried, but there were just too many errors. When I am reading a book on physics, I get very concerned when I find an error of an enormous magnitude in something that should be basic - the author is describing the distance to Alpha Centauri and lists it as 4 light years (correct) or 220 million km ???? That is less than a third of the distance to Jupiter at its closest. The figure is out by a factor of around 170.

Secondly, there are formulae in the book where the distinction between v and v' (for example) are not made clear, and this is an important distinction. Now, I assume that the author actually knows more physics than this, and these errors are most likely caused by not having an editor (or proof-reader) who is sufficiently au fait with scientific terminology and basic physics. I know this book was later released in paperback format, and I hope that these errors, and any other typographical and mathematical errors, were corrected for that edition. But I will never find out.

[Ellie Sorota]

so far - so good...and confusing