This slim volume consists of six essays, based on talks presented at the Kipfest on the occasion of Kip Thorne's sixtieth birthday. Thorne, the Feynman Professor of Physics at Caltech is best known to the general public for his 1988 wormhole "time machine" proposal, and indeed much of the book is taken up exploring the question, "is time travel possible?"

Physicist Richard Price leads off with a concise refresher-essay, "Welcome to Spacetime." Danish physicist Igor Novikov explores classic time-travel paradoxes, with some cool diagrams and novel results: in essence, "closed timelike curves" 2 are theoretically possible, but paradoxes aren't allowed -- with a time-machine, you could visit your grandfather, but you couldn't kill him. The universe wouldn't permit it -- which in essence is Hawking's Chronology Protection conjecture. Hawking speculates that the unfortunate time-traveler would be incinerated by (literally) a bolt from the blue. Well, what he actually says is, "one would expect the energy-momentum tensor to be infinite on the Cauchy horizon" , which (sigh) is a pretty typical Hawking attempt at "popular" science.

Fortunately, Thorne himself is a master popularizer, and he ends up explaining Hawking's ideas as well as his own. His essay amounts to an update chapter for his wonderful 1994 book, Black Holes & Time Warps: Einstein's Outrageous Legacy, which I enthusiastically recommend. Thorne reluctantly concludes that things really don't look very good for wormholes, especially for time travel -- though he does leave a tiny ray of hope for some super-advanced future civilization to make wormholes for space travel . Thorne notes that our grasp of basic physics is so crude that we can really only understand maybe 5% of the stuff that fills our universe -- the "normal" baryonic matter that makes up people, planets and stars. Thorne guesses that 35% of the universes's mass is in some unknown form of "cold dark matter", and the remaining 60% is some even more mysterious form of "dark energy" -- so there's certainly plenty of room left for discovery!

The book concludes with a nice explanation of why good popular-science books are needed, by noted pop-science writer Timothy Ferris, and with Alan Lightman's essay on "The Physicist as Novelist". Lightman, a former student of Thorne's, went on to write Einstein's Dreams and other well-regarded novels.

The Future of Spacetime is written for a general audience -- aside from Hawking's essay, everything should be understandable to any science-literate reader. I particularly recommend it to readers who've liked Thorne's earlier pop-science works. 3.5 stars, rounded up.

My 2002 review: https://www.sfsite.com/11a/fs139.htm

I am reading

3.8

these essays are all over the place. there's a 50-page introduction that tries to teach you the basics relativity, but it's much too numbers-based and super-boring -- i can't imagine any layman would get much out of it. but at least then you figure that you're going to get five hardcore physics lectures.

which the first two are, by hawking and novikov. they were quite enjoyable serious discussions of time-travel -- whether it might be physically possible and what about the whole "going back and killing your grandfather" paradox -- and i almost gave the book 3 stars for them.

but then the kip thorne essay has some physics but is just a list of predictions and him listing all his "russian friends" and eminent former students and how great his projects are and how cool his friends are. so then he must be cool, too, right?

then the book really goes into the tank. the last two essays have nothing to do with relativity at all. tim ferris writes about how important science writing is (he being a science writer). and finally alan lightman (author of Einstein's Dreams and PhD in physics) writes this excrutiating essay about how wonderful it is to be a novelist who used to be a physicist. i.e., how wonderful it is to be himself. i was thinking of reading Einstein's Dreams, but the guy seems like such an egomaniac that now i don't think so.

if this is at your library, get it for the hawking and novikov. but don't buy it.

Five talks given at Caltech in celebration of Kip Thorne's sixtieth birthday. The talks by Novikov and Hawking are on the possibility or impossibility of time travel, and don't go much beyond the treatment in Thorne's book. The talk by Thorne himself is a number of predictions as to what he expected would be discovered about black holes and gravity waves by 2010 or 2015, mainly by the NASA/ESA LISA satellites, leading up to a theory of quantum gravity by 2020 -- about five years later than Smolin's prediction, and equally wrong. (LISA was scheduled to be launched in 2010, but was delayed by NASA budget cuts and the project was eventually cancelled in 2011; ESA may launch its own version without NASA's help some time after 2020.) The talk by Ferris is on popularizing science, and the one by Lightman (a physicist and novelist) is on the resemblances and differences between science and literature; these were actually the most interesting. Not a serious study of anything, but a fast and fun book to read.

This is a kind of festschrift for the famous theoretical physicist Kip Thorne, on the occasion of his 60th birthday, published in 2002. The essays vary widely in style and subject. The one by the even more famous theoretical physicist Stephen Hawking tries to explain to the layman how time travel via wormholes ("closed timelike paths") might be possible--completely without success, as far as I'm concerned. Perhaps the most interesting is the one by the honoree himself. in which he makes a number of predictions about the near future of quantum physics. He predicts the detection of gravitational waves, which happened in 2016 (and resulted in Thorne winning the Nobel Prize in 2017). He predicts a consequent explosion of understanding of high-mass cosmic events; perhaps this is underway in his rarified circles. He predicts another decades-long explosion from the detection of gravitational waves from the Big Bang. On the other hand, he also predicts the solution of quantum gravity by 2020, and we're still waiting.

The Future of Spacetime is a collection of essays written by Kip Thorne's friends for Thorne for his birthday. Some of the essays are brilliant, others are rehashings of previous writings and the rest are difficult to follow. I will keep this book to reread some of the essays.

This is a collection of articles dealing with leading edge problems in spacetime physics, and they were written by physicists who are active in the field. I thought this book was written for a non-scientific audience and would be an easy read. It wasn't. You don't need a degree in physics to read this, but you do need to be well informed on relativity, quantum mechanics and black holes. If you are looking for a casual read on physics, this isn't it. This book was part of celebration of Kip Thorne's birthday, and was published by Cal Tech. (Kip Thorne is a world renowned physicist.) The articles were written by and for him and his associates. Be prepared to be mentally challenged.

Having said all that, I found this to be a well written and informative book.

Six pieces here of varying interest. A long and detailed technical introduction precedes the five essays, including three about spacetime.

Kip Thorne offers the most accessible essay of the three science entries here. He includes practical analogies and good drawings that illustrate his predictions and speculations. Thorne deserves top billing of this anthology.

Timothy Ferris wrote about the popularization of science. He tells how reasoned and open-minded inquiry replaced fear, superstition and blind obedience to authority. Meanwhile, modern scientific illiteracy reveals itself when half of all Americans deny that humans evolved from earlier animals. Fewer than seven percent of Americans are scientifically literate, Ferris wrote, while forty percent still believe in astrology.

Three and a half stars: Three stars for the book but four stars for Thorne and Ferris, who wrote the most interesting essays in this collection.

Loved the ideas.

4 gracious essays from incredible physicists

Well written essays that provide a super-high level overview of the topics. Technical writeup isolated to first four chapters.