Re: Bulges

[Gary Karshner <karshner@stmarytx.edu>]

> Am I wrong in thinking that the usual attribution of TWO tidal bulges is to
> Newton?  And he did this by recognizing that the Moon/Earth system revolves
> about the mutual center of mass. This is certainly the presentation in
> various physics texts.  But I don't find these thoughts in the Principia. 

Jim,
        Galileo, had the Tidal theory wrong with only one hig and low tide
per day. Both his friends and advisaries tried to correct him to no avail. A
fact that makes one wonder if he followed his own method.
        Edmund Halley, the editor/publisher of Newton's Principia is
credited with generating the first accurate tide tables for England. A feat
that requires both a knowledge of the position of the earth's tidal buldge
and the rate of flow of water into and out of rivers, bays and harbors.
        It is of course the gradiant and not the magnitude of the force that
dtermines the size of a tide, as one of my astronomy students point out when
he noted that otherwise the solar tide would be greater then the lunar one.
        I hope this helps.
Gary
 
Gary Karshner

St. Mary's University
San Antonio, Texas
KARSHNER@STMARYTX.EDU