From: carl@SOL1.GPS.CALTECH.EDU (Carl J Lydick)
Newsgroups: sci.skeptic
Subject: Re: Some Real Physics (Was: Re: Of Egg Yolks and Astrology)
Date: 3 Oct 92 21:33:20 GMT
Reply-To: carl@SOL1.GPS.CALTECH.EDU
Organization: HST Wide Field/Planetary Camera
NNTP-Posting-Host: sol1.gps.caltech.edu

In article <30SEP199211494188@csa1.lbl.gov>, sichase@csa1.lbl.gov (SCOTT I CHASE) writes:
=In article <BvCL3L.IEB@watserv1.uwaterloo.ca>, shallit@graceland.uwaterloo.ca (Jeffrey Shallit) writes...
=>In article <1a0jrsINNqp7@usenet.INS.CWRU.Edu> ak104@cleveland.Freenet.Edu (Robert Clark) writes:
=>>
=>>
=>> Proponents of astrology have used the argument that the different
=>>gravitation pulls of the Sun and the Moon on the Earth at different
=>>times of the year could be used to explain the alleged differences
=>>in personality by birthdate. They cite the enormous gravitational
=>>influence of the tides to show how fluids on the earth, and by
=>>extrapoloation fluids in our bodies, are affected by astronomical
=>>objects. 
=> 
=>Yes, we can be sure-- when the gravitational pull of the doctor/midwife
=>who delivered you is greatly exceeds the total gravitational pull of the
=>other planets.
=
=Come on. This is just not true.  Have any of you gugs who believe this
=actually tried to work out the numbers?   Geez.
=
=Sun vs. Doctor:
=
=Doctor:  100 Kg at 2 feet from the baby.
=Sun:     2E30 Kg at 9.3E7 miles from the baby.
=
=The gravitiational force, G, of the Sun is down by a factor of 
=ratio of distances squared = ((9.3E7*5280)/2)^2 = 6E22.  That's a big
=loss due to distance.  On the other hand, G for the sun is larger due
=to it's HUGE mass by a factor of the ratio of the masses = (2E30/100) = 2E28.
=So the bottom line is that the Sun has a pull more than 300,000 times the
=pull of the doctor.  

But since the patient/Earth system is in free fall wrt the Sun, while the
doctor and the patient are not in free-fall wrt each other, we should be
comparing the gravitational effect of the doctor with the tidal effect of the
sun.  I think you'll find that in that comparison the doctor loses by only a
factor of 26 or thereabouts, since the tidal force goes down as the cube of the
distance between objects, and is proportional to the size of the object
experiencing the tides (in this case the patient/Earth system).  With the sun
barely winning out over the doctor, the planets don't stand a chance.

=(2) Gravitation is so weak that the only significant sources of gravity are
=the few huge objects in our solar neighborhood.  Small objects (doctors, 
=skeptics, astrologers, etc.) are negligible, even at close range.

And tides are so much weaker that even large objects (e.g., the sun) at large
distances exert tidal forces that are comparable to the gravitational forces
exerted by nearby skeptics, astrologers, etc.
--------------------------------------------------------------------------------
Carl J Lydick | INTERnet: CARL@SOL1.GPS.CALTECH.EDU | NSI/HEPnet: SOL1::CARL

Disclaimer:  Hey, I understand VAXen and VMS.  That's what I get paid for.  My
understanding of astronomy is purely at the amateur level (or below).  So
unless what I'm saying is directly related to VAX/VMS, don't hold me or my
organization responsible for it.  If it IS related to VAX/VMS, you can try to
hold me responsible for it, but my organization had nothing to do with it.
Newsgroups: sci.skeptic,talk.religion.newage