[geocentrism] Re: Several posts
- From: Mike <mboyd@xxxxxxxxxxxx>
- To: geocentrism@xxxxxxxxxxxxx
- Date: Wed, 13 Oct 2004 02:42:10 +0100
Dr. Neville Jones wrote:
>> " I'll ... try to confine myself to talking about your ideas which is
>> why I'm here afterall."
>
> I'm flattered that you should be interested in talking about
> them at all, and I'm also encouraged by it.
Well I'm actually being a bit selfish here. I find that discussions
with people of such differing views as mine actually helps me to clarify
what I assume, what I can derive and what I need to mug up on. I hope
that doesn't sound patronizing, it wouldn't work if you weren't able to
make me question my own point of view.
> I would like to replace your "standard" with "conventional,"
I originally wrote that and then replaced it with "standard", convential
is fine by me.
> perhaps a good way of elaborating upon this difference
> between us is to stick with the ice skater. The ice skater is to all
> intents and purposes a rigid body. She moves en mass. Ignoring the
> friction between her boots and the ice again, you accept that she
> slows down because she has imparted some of her angular momentum to
> the air around her. My question to you is simply this: how does the
> air around her, which is not rigid, but gaseous, then impart its
> angular momentum back to her?
It doesn't. Their *total* angular momentum is conserved. A gross over
simplification: -3 + 3 = 0, -1.5 + 1.5 = 0, -0.75 + 0.75 = 0 ..., 0 + 0
= 0. You can add an arbitrary n to all the terms there, you get what I
mean yeah?
> I know that you have indicated the need
> for a statistical, Brownian motion-type analysis, but surely there
> must be an overall transference of angular momentum in this system
> from the skater to the air and, since the air is not in a "closed
> system" even with the World and its atmosphere (because of thermal
> radiation, meteorites, gravitational effects, for example), over time
> the skater (or World), loses more than she retreives and slows down
> to a stop.
That sounds like an entropy argument. And your last sentence is
treating the skater as if she is a closed system after considering her
interaction with the atmosphere - she looses angular momentum, the
atmosphere gains it, the atmosphere looses it to the earth, they
eventually all have the same angular velocity but throughout their
*total* angular momentum is constant.
If you idealise the situation and only consider the world, the skater
and the atmosphere then do you agree that angular momentum is conserved?
Whatever else you introduce, if you include this throughout in a
greater, idealized, closed system do you agree that angular momentum is
also conserved? If not please point to where it is lost in a *closed*
system.
Regards,
Mike.
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