Now we have to ask the obvious question of why the disc is the usual common geometry in astronomy.
Where we have galaxies in discs of spiral galaxies or barred spiral galaxies or lenticular galaxies.
In the Solar System we have the disc of the Ecliptic that contains the Sun and its planets.
On the planet Saturn we have the disc of the Rings of Saturn.
So why is the astronomy so much of its geometry disc shaped?
The answer is that gravity is EM-gravity of the Maxwell Equations. When you plunge a bar magnet into the disc of a closed loop wire you get a electric current flowing in that wire. When you have a closed loop of wire and you run an electric current in the wire you have discs of magnetic fields around the wire.
The Maxwell Equations of electricity and magnetism is all about a geometry of electricity interplaying with magnetism and in the interplay are discs, discs of magnetism and discs of electricity. --
Google's (and Bing's) searches and archives are top-heavy in hate-spew generated by search-engine-bombing. Google has never made searches fair from bombing practices placed on innocent people. The way to make searches fair is to have transparent true names behind all authors of either Web or Usenet. When people can hide behind fake names or omission of true identity, you end up with massive hate spew. And the Google author-archive stopped functioning properly by about May 2012. And recently Niuz.biz (Docendi.org) threatens to harm your computer if opening a post of mine. The solution to the sci. newsgroups is to have the sciences hosted by colleges and universities such as Drexel University hosting sci.math, not by corporations like Google and Microsoft out to make money. And every post should have a true legal name.
Science belongs in education, not in money motivated corporations. Do I hear a?University doing sci.physics, sci.chem, sci.biology, sci.geology, etc Only Drexel's Math Forum has done a excellent, simple and fair archiving of AP author posts for the past several years as seen here: