Spacetime Physics

LibraryThing Review

Recommended by Brian Greene in his book Fabric of the Cosmos. This is a 1992 textbook suitable for students/readers with an algebra background. It focuses on the main equation of invariance (aka ... Read full review

Throughout this book, John Wheeler demonstrates proficiency at problem solving and extreme dysfunction regarding fundamental concepts. This dysfunction comes into sharp focus on pages 76-77, where he says "Absolutely not!" to actual clock slowing due to free-float motion, while maintaining that clocks whose relative motion was due entirely to free-float motion show an actual disparity in their clock readings upon reuniting.
This book fails at the very core of relativity. Wheeler makes two long attempts (pages 125-131, 169-170) to resolve the Twin Paradox and fails, due to his failure to utilize absolute light speed in an absolute frame of reference, which Wheeler doesn't seem to realize precludes any such paradox, though it be completely consistent with Einstein's relativity. He should have followed Einstein's lead and not attempted any resolution of the Twin Paradox so long as he held to Einstein's original narrow interpretation, which was strictly that of symmetrical measures across inertial frames.
He fails to note that only an actual difference in clock rates can bring about an actual difference in the readings of two reunited clocks.
Furthermore, it is a trivial matter to show that an observed asymmetry in time keeping difference builds incrementally (the difference first noted at the moment of turn-around) when the two parties in question continuously update each other on the status of their clocks via radio signals. There simply is no observed "jump in time", as Wheeler claims, regarding the other party's clock.
Wheeler turns himself inside out over the course of seven pages (125-131), only to fold his arms on page 131 and proclaim “40 years for the astronauts, period. 202 years for the Earth, period. End of story.” .... in “the common language of proper time, every observer agrees.”
Okay. They agree. They are all looking at the discrepancy in the watches at the same place-moment once back on Earth; how can they not agree? But they have no explanation for where the missing time went, because Wheeler has proclaimed that no one's watch ran any slower than anyone else's.
Wheeler claims to have resolved the issue on page 131, yet he must have recognized that he actually had not, for on page 169 he writes that he's going to "clear up - once and for all! - the solution to the Twin Paradox". On page 170, he writes that he will "finally!" solve it.
But the same convolution plays out. He fails to incorporate simple things such as having the two parties send radio signals to each other to keep track of time-keeping (which would lead to the noting of an incrementally increasing time differential, first noted at the turn-around), and having the outbound astronaut transfer clock information to an inbound astronaut. Instead, he again claims: "The astronaut has nobody but herself to blame for her misperception of a "jump" in the Earth clock reading". Her "misperception" is due to her "inheriting a new set of colleagues" in her inertial frame strung out between herself and the Earth, each of them noting Earth's clock time as they pass by it.
The only thing he accomplishes with this lattice of clocks method (based on Einstein's method for clock synchronization) is to repeat Einstein's original conclusion of lesser recorded time for the party that changes frames.
But the paradox he is supposed to be resolving is the question of how one clock will record less time than the other without admitting that the clocks in question actually did tick at different rates. Unlike the silent Einstein, Wheeler maintains that the astronaut's clock did not actually run at a lesser rate, despite the lesser registered time and no accelerations involved.
Wheeler of course cannot explain how such a "misperception" of a "jump in time" (which cannot even occur using a rational measuring paradigm) could possibly create an actual difference in clock