[net.origins] Even Amateurs Should Understand Dynamics

mangoe@umcp-cs.UUCP (Charley Wingate) (10/28/85)

In article <446@imsvax.UUCP> ted@imsvax.UUCP (Ted Holden) writes:

>    As I stated in the article, it's the amateurs who have these problems
> with the laws of physics....  I certainly haven't given up my belief in
> gravity;  the moon causes tides, Venus which is larger than the moon once
> caused all hell to break loose on this planet (as can be read in "Worlds
> in Collision), and Saturn, even in it's present state, is much larger than
> either.  I am simply leaving open the possibility that forces OTHER than
> gravity itself may have played a role in the state of affairs,
> gravity-wise, which prevailed on this planet prior to the flood.

Unfortunately, it isn't forces that are the problem at all-- it's dynamics.
Suppose Venus HAD come from outside Earth's orbit and had passed Earth
relatively closely.  This immediately (assuming an initial orbit even
remotely like the current one) causes a tremendous perturbation in the
orbit.  Now you have a tremendous eccentricity in the orbit, which you have
to transfer to some other body to restore the original orbit.  Venus, on the
other hand, has got to get rid of a similar amount of momentum to come to
rest in it's current orbit.

The notion of an encounter at any distance with Saturn is simply
preposterous  (it's been years since I looked a V.'s stuff, so just
disregard this if it is irrelevant).  An inner solar system passage of
Saturn is quite sufficient to expell every minor planet, including earth,
from the solar system-- and without affecting Saturn at all, giving us (once
again) a pile of momentum to deal with-- in this case, we need to acquire it
to restore the current orbit.

Other forces simply don't matter.  If you've ever played with orbital
dynamics games, it should be apparent that inverse square laws (and
remember, folks, those are the only kind that work over these distances)
don't do the trick.  You need to split or merge bodies-- and on a split, one
body must be "thrown away", to get rid of the momentum, for the other to
orbit non-eccentrically.

Charley Wingate