🚀 go-pugleaf

Why do the planets, and other bodies, revolve around our star in a
relatively two-dimensional plane?  By this, I mean the orbits of the
planets (as well as astroids, etc.) seem to form a collective flat
disc when modeled (I know Pluto's orbit is a little bit askew).  Why
not orbit three-dimensionally?  A lot of galaxies and everything else
related also seem to be rather two-dimensional in shape.  Is this just
a property of gravity that really has no explaination?

I'm asking this just out of curiosity.  I'm not yet very knowledgable
in this subject.

Thanks,
John
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