Who uses Ellipses?

Date: 12/3/95 at 21:3:54
From: Anonymous
Subject: ellipses

I need to find out who (or what occupation) uses ellipses in their 
work.  There isn't anybody like that I know.  Could you help me 
find one and what they use it on and what it is for?

Thank you 

Date: 7/12/96 at 9:49:46
From: Doctor Alan
Subject: Re: ellipses

One area where the study of the ellipse is important is astronomy. 
Ellipses describe the fundamental motion of the planets around a 
star, such as our planets and the sun.  The orbits of planets are 
not circular, but of an elliptical nature with the sun located at 
one of the foci. The eccentricity of these ellipses is normally 
close to unity so they appear as a circle; however, they are 
ellipses.  Comets also follow an elliptical orbit with usually a 
much higher level of eccentricity.

-Doctor Alan,  The Math Forum