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Re: lawless physics (fwd)



On Mon, 16 Mar 1998, Igal Galili wrote:

John,
Would you mind to add few words to your statement, which I admit, I could
not follow:

I try to make sure that students come away
from the course understanding the important fact that there is *no* limit
on "how fast" you can get from one place to another (which is all that can
possibly matter to a traveler) and, therefore, precious little meaning to
the notion that nature imposes any kind of "speed limit."

Igal,

I'm not sure I know what it is that you don't follow here. You *do*
understand, don't you, that a person can, in principle, travel from one
object to any other in an arbitrarily short time within the framework of
special relativity.

and especially:

The fact that
no observer can *measure* a material object to be traveling faster than
the speed of light is a statement about *measurements* of space and time,
not about "how fast something can move."

Do you distinguish between "the true movement" and "the measured one"?

Of course. Measurements of motion have well defined operational meaning.
What could it *possibly* mean to talk about "true movement" within the
framework of special relativity?

And since one person's "faster
than light" is another person's "backward in time," all that nature is
really proscribing is causality.

Do you want to say that the formalism of the special relativity does not
collapse for v>c and it is only causality that forces us to reject such
speeds for material objects?

There are some other problems with v>c, but that's surely the big one!

John
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A. John Mallinckrodt http://www.intranet.csupomona.edu/~ajm
Professor of Physics mailto:ajmallinckro@csupomona.edu
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