Yes. Quasars are the size of the solar system.
Yes, a average quasar is the size of our solar system
Quasars
No, quasars are not part of the solar system. Quasars are extremely distant and energetic objects located in the far reaches of the universe, millions or billions of light years away from our solar system. They are powered by supermassive black holes at the centers of galaxies.
Astronomers determine the size of quasars by analyzing the variability of their light. Quasars show rapid and dramatic changes in brightness over short periods, indicating that they must be very compact, likely smaller than our own solar system. By studying the time scales of these changes, astronomers can estimate the size of quasars.
Saturn is the second largest planet in the Solar System, next to Jupiter.
Scientists classify small objects in the solar system by size, shape, and composition
Of the eight planets in our solar system, Earths is the fifth largest or the fourth smallest.
It isn't. Earth ranks 5th in size. Jupiter is the largest planet in the solar system.
Mercury
Empty space.
The Earth is a planet if that is what you are asking. It is a planet in our solar system. However compared to the the relative size of other planets in the solar system earth is quite an average size.
Quasars are believed to be gigantic black holes - millions of times the mass of our Sun. If we were anywhere near a quasar, it would be more accurate to state that the Sun (or the Solar System) revolves around the quasar, not the other way round.