"Elenin" comet trajectory diagram ...

http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=C%2F2010%20X1;orb=1;cov=0;log=0;cad=0#orb

 

I find that remarkable in that the elliptical orbit is in the same plane as the solar system. It is probably not that unusual although I had somehow been under the impression that comets weren't native from the development of our own system's orbits, that they were far raging captures.
We don't have the apoapsis of the perihelion in that diagram.

 

I don't know much about astrophysics, but I'm guessing that the mutual gravitational relationships between objects around a central gravitational object create the plane. Like the rings of saturn, all that stuff is attracted to saturn but also to the other material.

Likewise, the planets have planar orbits, because the planets are also chasing each others gravitational pull as well as the sun's.

 

cool stuff i just hope one doesn't hit us