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Re: starship-design: Re: FTL travel
Curtis Manges writes:
> Steve VanDevender wrote:
> > See pages 201 and following in the second edition of Taylor and
> > Wheeler's _Spacetime Physics_.
> For the sake of anyone who sees these pages, please find a better book to
> recommend. I bought a copy about a year ago and soon threw it away. A friend
> of mine agreed with me that this is not a book of science, it is a book of
> dogma (INVARIANT INTERVAL), chiseled in stone, and supported mostly by
> comments, the gist of which is, "believe it because we say so" and
> "everybody knows . . .", and extending to the insidious technique of
> training the reader to defend its precepts against logical argument. It also
> wasted very extensive space on pointless discussions of paradoxes. This book
> taught me almost nothing about physics, but was quite enlightening in
> brainwashing and propaganda techniques. Even the opening parable of the
> Daytimers and the Nighttimers concludes wrongly (that they would be in
> agreement: they won't, because they will still be using different
> references). Frankly, I've read religious tracts that were more
> intellectually appealing.
I think I know where you're coming from, to the extent that I've seen
you express support for "alternative" physical theories like
I think _Spacetime Physics_ expresses the formulation of relativity that
is in mainstream physical thinking, and its explanations are much
clearer for beginning students than those in other texts I've seen.
It's no more dogmatic than any other physics text I've read; what you
call dogma I see as emphasizing the simple fundamental ideas behind
relativity theory. Invariance of spacetime interval in relativity is
just as fundamental an idea as the invariance of distance in Euclidean
geometry; the parable of the daytimers and nighttimers is meant to
emphasize that while you can choose different coordinate systems in
which the same location has different coordinates, there are geometrical
invariants that apply to any of coordinate systems one might choose.
Similarly, in different relativistic frames, one measures different
coordinates for the same events, but the spacetime intervals between
events that one obtains from those different coordinates is the same in
all frames. And since a great source of confusion in students who are
learning relativity are things like the seeming twin paradox, spending
time on explaining why the seeming paradoxes aren't really paradoxes
makes a lot of sense to me.
> I am not a scientist, but I do consider myself a critical thinker, and your
> continued support of this book is undermining my estimation of your own
> credibility. There are better books out there, I'm sure; please find a
> different one to recommend.
I think anyone who studies the history of science knows that while many
scientists in a particular time think they have the definitive laws of
physics, what science does over time is obtain an increasingly precise
understanding of the underlying laws of nature. Newtonian physics was
successful for so long because every experiment that was possible to do
during its reign confirmed its results; the major hurdle relativistic
physics had to overcome to be accepted was obtaining the experimental
proof that showed it worked better than Newtonian physics in the domains
that previous experiments had been unable to test.
If something better than relativity is to come along, to be accepted it
will need to make predictions measurably different than relativity, and
then have those predictions be proven by experiment. I don't promote
relativistic physics because I think it's the be-all and end-all of
physical theories; I promote relativistic physics because it's clearly
the best experimentally-verified theory we have now. I'm willing to
change my mind when something better comes along, but I haven't seen
the better thing yet.