The outer limit of the Oort cloud, which begins about one-quarter of the distance to Proxima Centauri (and about one thousand times farther out than the Kuiper Belt), defines the cosmographical boundary of the Solar System and the region of the Sun's gravitational dominance.
Although no confirmed direct observations of the Oort cloud have been made, astronomers believe that it is the source of all long-period and Halley-type comets entering the inner Solar System and many of the centaurs and Jupiter-family comets as well.
I envision the journey out of the Milky Way into the great beyond . . . and as always, need a soundtrack for the trip.
Image: Painting by Don Dixon, http://cosmographica.com/gallery/portfolio2007/content/328_OortCloud_large.html
