[ExI] The Great Silence again

spike spike66 at att.net
Tue Apr 26 23:12:11 UTC 2011


... On Behalf Of Keith Henson
Subject: Re: [ExI] The Great Silence again

On Tue, Apr 26, 2011 at 2:37 PM, Anders Sandberg <anders at aleph.se> wrote:

snip

>> For the sun and 99% efficiency, that is 1.27*10^18 kg m/s^2. Putting 
>> that into F=ma gives us the whooping acceleration 6.39*10^-13 m/s^2.

>I got 13 x 10^-13 m/s^2 by totaling the radiation pressure over a 1 Au
sphere at 9.15 N/km^2.

>I wonder if one of us left out a factor of two.?  Keith


Keith, I think the factor of 2 in that approach comes from the fact that the
light pressure cycles between that maximum you have and zero, so the average
light pressure is half.  Don't know however.  I used a different approach
from both yours and Anders' and the ~600 meters per square year agrees with
what I had then.

spike




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