How big is our solar system?
It depends on if you consider the oort cloud to be our solar system.
If you consider the oort cloud, our solar system goes out about 100,000 au. An au is the distance from the sun to earth and is about 7 light minutes (which means it takes light 7 minutes to get from the sun to earth).
If you don't consider the oort cloud, Eris is the farthest notable body with an orbit of about 68 au.