RE: Aluminum Sphere for sale

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: gary350@xxxxxxxxxxxxx 

There is a 3 side triangle where the pointed corners are made 
round.  I am not sure what this shape is called.  The diameter 
through the middle is the same all the way around the 
triangle.  Sounds to me like according to one defination that the 
diameter of a sphere is equal all the way around then this 3 sided 
thing is a sphere too.   To bad I can not draw a pic and post it 
here.  There use to be some pics on the MIT web page.

Gary



-----Original Message-----
>From: Tesla list <tesla@xxxxxxxxxx>
>Sent: Mar 17, 2006 12:40 PM
>To: tesla@xxxxxxxxxx
>Subject: RE: Aluminum Sphere for sale
>
>Original poster: "Godfrey Loudner" <ggreen@xxxxxxxx>
>
>Circles (spheres) can be considered as a special cases of ellipses
>(ellipsoids) respectively. An ellipse has a major axis and minor axis.
>If the major axis equals the minor axis, then rotating the circle around
>either axes will trace out a sphere. If the major axis is not equal to
>the minor axis, then rotating the ellipse around the major axis (minor
>axis) will trace out a prolate spheroid (oblate spheroid) respectively.
>A prolate spheroid (oblate spheroid) appears like a football (doorknob)
>respectively). Spheres, prolate spheroids, and oblate spheroids are the
>ONLY cases of ellipsoids which can be obtained by rotating ellipses
>around either of their major or minor axes. HOWEVER there are ellipsoids
>which CANNOT be obtained by rotating ellipses around their axes. One
>example is x^2 + y^2/4 +z^2/9 = 1.
>
>Godfrey Loudner
>
>-----Original Message-----
>From: Tesla list [mailto:tesla@xxxxxxxxxx]
>Sent: Friday, March 17, 2006 8:09 AM
>To: tesla@xxxxxxxxxx
>Subject: Re: Aluminum Sphere for sale
>
>
>Original poster: FIFTYGUY@xxxxxxx
>
>In a message dated 3/16/06 8:06:30 PM Eastern Standard Time,
>tesla@xxxxxxxxxx writes:
>
>  >Ellipsoid: a 3-dimensional object generated by rotating an ellipse
> >about its major or minor axis. All plane sections are ellipses.
>
>      Couldn't a section through an ellipsoid be a circle, if that
>circle had as its radii the other ellipse axis?
>      And aren't circles a subset of ellipses?
>
>-Phil LaBudde
>(Gary could advertise them as "sphere-ish"?)
>
>
>