What defines the boundary of the solar system?
What do we mean when we say something has an edge, or a boundary? Some things, like a table or a soccer field have clear edges and boundaries. Other objects, like cities and towns, have boundaries that aren’t as easy to see. It is hard to say where they end and something else begins. The solar system is more like a city than a table or soccer field. You could say that the solar system extends as far as the influence of the Sun. That could mean the influence of the Sun’s light, or the influence of the Sun’s gravity, or the influence of the Sun’s magnetic field and solar wind. Could the reach of the Sun’s light be a good way to decide how far the solar system extends? The light from the Sun gets fainter as you move farther away, but there is no boundary where the light stops or where it suddenly gets weaker. How about gravity? Just like light, the influence of the Sun’s gravity extends without limit, although it gets weaker farther away from the Sun. There is not a boundary at which it s
