* No defined edge: The solar system doesn't have a clear-cut boundary. It's more like a gradual thinning out of the Sun's influence and the presence of objects.
* Different definitions: Scientists use different definitions for the edge of the solar system. Some use the heliopause (where the Sun's solar wind meets the interstellar medium). Others consider the Oort Cloud, a hypothetical spherical cloud of icy objects, to be the outer limit.
Here are ways we *estimate* the size of the solar system:
* Distance to furthest objects: We use the distance to known objects like the dwarf planet Eris or the heliopause (estimated to be around 123 astronomical units (AU) from the Sun) as a measure of the solar system's size.
* Gravitational influence: We consider the Sun's gravitational influence, which extends much further than the heliopause. However, it's difficult to define where this influence becomes negligible.
So, rather than a single measurement, we rely on different methods and estimations to understand the vast expanse of our solar system.
