And further out is the Oort cloud...extending 3 light years. Mighty big.
Interesting, since the nearest neighboring star is Proxima Centauri, about 4.2 LY away. So basically, matter from our solar system is bumping into matter from next door.
It's like the electron clouds in two atoms brushing each other, but the nucleus is way down at an almost infinitely removed ratio from the atom's "surface"; much like the planets in a solar system.
The Oort Cloud has never been seen, not even a little bit; so far it exists only as a kludge to account for blackboard problems with the conventional model(s) for planetary system formation. :’)