relative time travel

Gerry Quinn · 14 May 2011, 23:08 · from 2011-May.txt.gz

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From: gerryq at indigo.ie (Gerry Quinn)
Date: Sun, 15 May 2011 00:08:05 +0100
Subject: (urth) relative time travel
References: <4DCE1436.2090802 at io.com> <14958D9D0EAF4C1D86844D72152FF323@jill>
	<4DCEF2A9.9090604 at io.com>
Message-ID: <D29380BAED694F0782E2FC49181B497B@jill>

From: "Jeff Wilson" <jwilson at io.com>
> On 5/14/2011 10:08 AM, Gerry Quinn wrote:
>> From: "Jeff Wilson" <jwilson at io.com>

>>> 1. Each day, a train 600,000 km long (two light seconds) traveling north
>>> at 90% light speed pulls through a station 600,000 long without slowing.
>>
>> I'm not sure your figures are right here...
>
> ahem. "You guys that already know this will see that I have abstracted 
> numerous distracting features out of this account."
>
> This example is adapted from Richard Morris' TIME'S ARROWS
> http://www.amazon.com/Times-Arrows-Scientific-Attitudes-Toward/dp/0671617664/ref=sr_1_1?s=books&ie=UTF8&qid=1305407823&sr=1-1#reader_0671617664
> you can search for "lightning" to find his version that dodges length 
> contraction by having no background and no definite dimensions.  I tried 
> to include some of these to give the less accustomed posters fewer 
> indefinite things to envision at once.

I can search but it doesn't show me the pages.  That's beside the point, 
though. Weren't you trying to show that travel via a wormhole is time 
travel?  I don't think your illustration shows that.  In particular, you 
say:

"16. He arrives, unnoticed by "another" oppressed native who is intent on
a wristwatch and subsequently disappears in a puff of Molochian prayer."

Nope.   He arrives after he left - in my example, 0.4 seconds after he left. 
He doesn't ever meet himself.

To get time travel from instantaneous movement, you need a more complicated 
situation AND certain assumptions involving the reification of some concepts 
from special relativity, which are not provable in our universe, and which 
would certainly be false in a universe in which instantaneous travel was 
possible.

- Gerry Quinn
.

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