### Re: Why do the planets continue to revolve?

Article: <59q2rb\$qcq@sjx-ixn10.ix.netcom.com>
From: saquo@ix.netcom.com(Nancy )
Subject: Re: Why do the planets continue to revolve?
Date: 25 Dec 1996 02:17:15 GMT

In article <59fmbc\$rev@boursy.news.erols.com>Harry states:
> Planets (1) rotate on their axes & (2) revolve about Sun. Reason
> why the rotation persists is that the planet is like a frictionless
> wheel. Watch how a well-oiled bicycle wheel continues to spin when
> the wheel is not touching the ground. As for the persistence of
> revolution, the planet would move in a straight line if it weren't
> for the Sun's gravity. As it is, the gravity prevents the planet from
> running out to infinity, but it gets pulled into a curved path, and
> the planet's centrifugal force balances the gravity.
> Harry Hickey <hwhickey@pop.erols.com>

(Begin ZetaTalk[TM])
Tut, tut, there are several problems with this argument. A well-oiled bicycle wheel will spin quite a long time, indeed, especially if balanced in a nice parallel to the ground, but it DOES slow down and stop, and much before you can well walk away from it. This has less to do with the friction of the air and any drag the gravity of the earth may have upon it, and more to do with the rubbing parts, however well oiled. The incremental effect of a drag is such that it is at first slight, countered by the speed of the motion, and then increases rapidly as the motion slows down.

You haven't addressed the issue we raised, Harry, which is that there is a pull BACK on the revolving planet, due to the fact that whenever the planet is adjusted OUT of its straight line path, it is pulled BACKWARDS. We will ask our emissary, Nancy, to repost that argument, which has yet to be addressed, although there was a valiant try from one among the brave here on sci.astro.
(End ZetaTalk[TM])

As requested, the resposting of the Zeta triangle argument.

(Begin ZetaTalk[TM])
The gravity tug is not strictly a sideways tug, as in all cases the planet's path is pointed AWAY from the sun, however slightly. For any given instant moment: 1) draw a line representing the planet's straight line path, 2) draw a second line representing the path the planet is being set upon by the gravity tug, essentially a second tangent to the sun, 3) the angle between these two lines is the degree of BACKWARD TUG that the planet is experiencing.
(End ZetaTalk[TM])

To which Ken responded:

In article <59hf9r\$mh1@mcmail.CIS.McMaster.CA> Ken Knickerson writes:
> The only hard thought I can reply to here is the statement that the
> orbiting body's tangent path and the line of gravitational pull
> demonstrates a drag on the orbiter. In fact, the drag would go as
> the cosine of the angle between the lines (actually, a push for
> angles less than 90 degrees.. In a circular orbit, these lines are
> perpendicular, so no drag or boost is given to the body.
> nickerso@mcmail.cis.McMaster.CA (Kent Nickerson)

(Begin ZetaTalk[TM])
Ah, math to the rescue, as the theoretical can replace the actual! Unfortunately, we won't be put off by your blitz. You have the straight line that your fellow humans have asserted the Earth wants to move in placed into so short a space of time that it DOESN'T EXIST. Tut tut! If it doesn't exist, then it can't be plugged into your formulas, so it must exist. No matter how tiny you make that instant, at the start of that instant the Earth is moving in a straight line, and at the end of that instant it is moving in a line at an ANGLE from the first. It is being pulled back toward the Sun, OFF its original path at the start of the instant. The Earth thus has a drag on its forward momentum.
(End ZetaTalk[TM])