There isn't a single, clear-cut edge to the solar system. Instead, it's more like a gradual fading out, with different boundaries depending on what you're measuring:

* Heliopause: This is the point where the solar wind, a stream of charged particles from the Sun, is no longer strong enough to push against the interstellar medium (the gas and dust between stars). It's roughly 123 AU (astronomical units) from the Sun, but its exact location can vary.

* Outermost planet: Neptune is the furthest planet from the Sun at 30 AU. However, there are many dwarf planets and other icy bodies beyond Neptune, including Pluto at 39 AU.

* Kuiper Belt: This region extends from 30 AU to about 50 AU and contains many icy bodies, including Pluto.

* Scattered Disk: This region extends beyond the Kuiper Belt and includes objects that have been scattered by gravitational interactions with planets.

* Oort Cloud: This is a theoretical sphere of icy bodies, thought to be the source of comets, extending as far as 100,000 AU from the Sun.

So, depending on what you're looking for, the "edge" of the solar system could be anywhere from Neptune's orbit to the Oort Cloud. It's important to note that our understanding of the outer solar system is still evolving, and new discoveries are constantly being made.