relative time travel

Jeff Wilson · 14 May 2011, 21:22 · from 2011-May.txt.gz

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From: jwilson at io.com (Jeff Wilson)
Date: Sat, 14 May 2011 16:22:49 -0500
Subject: (urth) relative time travel
In-Reply-To: <14958D9D0EAF4C1D86844D72152FF323@jill>
References: <4DCE1436.2090802 at io.com> <14958D9D0EAF4C1D86844D72152FF323@jill>
Message-ID: <4DCEF2A9.9090604 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...
>
> If these are the lengths observed by the native (as it appears), then
> the rest length of the train is more like 1,400,000 km. The mail agents
> will take this into account when discussing who acted first. In their
> frame of reference the station is only 250,000 km long. Logic will force
> them to conclude that the pickup happened first.

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.

-- 
Jeff Wilson - jwilson at io.com
Computational Intelligence Laboratory - Texas A&M Texarkana
< http://www.tamut.edu/CIL >

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