Re: What's wrong with this?

----- Original Message -----
From: "Donald Nield" <d.nield@auckland.ac.nz>
To: "George Murphy" <gmurphy@raex.com>
Cc: "Glenn Morton" <glennmorton@entouch.net>; "'Ted Davis'"
<tdavis@messiah.edu>; <asa@calvin.edu>
Sent: Monday, June 21, 2004 9:25 PM
Subject: Re: What's wrong with this?

>
>
> George Murphy wrote:
>
> > ----- Original Message -----
> > From: "Glenn Morton" <glennmorton@entouch.net>
> > To: "'Ted Davis'" <tdavis@messiah.edu>; <asa@calvin.edu>;
<gmurphy@raex.com>
> > Sent: Monday, June 21, 2004 8:00 PM
> > Subject: RE: What's wrong with this?
> >
> > > Darn, you got the gold star before me. But one addition. It was only
in
> > > free fall when it was on a geodesic path outside of the part of the
> > > atmosphere where enough atmospheric density could cause significant
> > > drag.
> > >
> > > > -----Original Message-----
> > > > From: asa-owner@lists.calvin.edu
> > > > [mailto:asa-owner@lists.calvin.edu] On Behalf Of Ted Davis
> > > > Sent: Monday, June 21, 2004 6:40 PM
> > > > To: asa@calvin.edu; gmurphy@raex.com
> > > > Subject: Re: What's wrong with this?
> > > >
> > > >
> > > > If this is a quiz, George, the answer is: It isn't
> > > > weightless, it's in free fall. Like the moon around the
> > > > earth, or the earth around the sun.
> > > >
> > > > Do I get a gold star or my pick of the toy bag??
> >
> > Ted & Glenn -
> > Not exactly. Objects in free fall _are_ weightless because in a
> > coordinate frame moving with them the gravitational acceleration has
been
> > transformed away locally. It doesn't matter how high you are - you're
> > weightless (except for the effects of air resistance) when you jump off
the
> > high dive. Astronauts train for weightlessness - or at least they used
to -
> > in planes that are in free fall (though perhaps moving upward &
> > horizontally - on a parabolic path) for a fraction of a minute.
> >
> > Shalom
> > George
> > http://web.raex.com/~gmurphy/
>
> So I take it that what was wrong in the original account was that
> "weightlessness" should have been replaced by something like "a
significant
> interval of sustained weightless"? Not a big deal, in my opinion. The
connection
> with YECs seems rather remote to me.

No, what was wrong with the CBS statement was the idea that weightlessness
has something to do with distance from the earth, as if it were a matter of
being "outside the earth's gravitational field" or something like that. (I
have seen that kind of assertion made explicitly in the past. It ranks with
the old claim that rockets couldn't work in outer space because there was no
air for the exhaust to push against.) & it doesn't. It shows a complete
misunderstanding of gravitation - not just of Einstein's theory (which
provides the best way of understanding the phenomenon) but even of Newtonian
theory (because of course 1/r^2 never goes to zero for any finite r). This
degree of misunderstanding, transposed to earth history &c, allows people to
think that humans were contemporaries with dinosaurs &c.

I apologize if my reaction seems to extreme but such things, stated
confidently by TV newspeople, make me go ballistic (so to speak!)

 Shalom
George
http://web.raex.com/~gmurphy/
Received on Mon Jun 21 22:16:02 2004