Re: I don't get it

kk says...

On Feb 23, 7:22=A0pm, Bryan Olson <fakeaddr...@xxxxxxxxxxx> wrote:
kk wrote:
Daryl McCullough wrote:

kk says...
After eliminating all accelerations, we are left with
nothing but plain inertial motion, so the question still
stands: What could cause people in different frames to
age differently?
They don't.

Wayne Throop (and all other relativists, only excluding
you) beg to differ:

http://mentock.home.mindspring.com/twins.htm

Here's the key part of Throop's cute triplet example:
"To avoid accelerations in the thought experiments above, we
can simply make the second Bob frame into a "messenger" Carl
[who] never accelerates, but passes by Bob as they set their
watches together. Messenger Carl then travels to Ann and
compares watches as they pass each other. That makes it clear
that there are three distinct inertial frames involved."

As I said clearly to you before: No accelerations and yet
the triplets age differently.

No, they don't. The triplet paradox does not show that
any of the triplets "age differently". If we label the
events as follows:

e_0 = Bob departs from the Earth at 3/5 c.
e_1 = Carl passes Bob.
e_2 = Carl reaches Ann (on Earth).

Let T_01 be the proper time to go inertially from e_0 to e_1.
Let T_02 be the proper time to go inertially from e_0 to e_2.
Let T_12 be the proper time to go inertially from e_1 to e_2.

The triplet paradox illustrates that
T_12 > T_01 + T_12

What this shows is that the amount of (proper) time required to
go from e_0 to e_2 depends on what path you take through
spacetime. Why is that at all surprising? The amount of time
required to drive from New York City to Chicago depends on
what path you take. Why shouldn't the time required to go from
e_0 to e_2 depend on the path taken?

--
Daryl McCullough
Ithaca, NY

.

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