Astronomy Practice Exam 2025 – Complete Preparation Guide

The solar system is defined as the Sun and everything that orbits around it, which includes planets, moons, asteroids, comets, and other celestial bodies. The Sun, being the central star, exerts a strong gravitational pull that keeps these objects in stable orbits. This vast region is characterized by a complex interplay of gravitational forces, with the Sun at the center and varying types of bodies moving in orbits of different shapes and sizes.

The other options do not accurately represent the structure of the solar system. The mention of planets and moons in isolation disregards the importance of the Sun as the pivotal element of the system. The idea of a collection of galaxies in a cluster refers to a much larger cosmic scale and does not pertain to the solar system, which specifically consists of one star and its orbiting bodies. Lastly, a mixture of stars without any orbiting bodies misrepresents the nature of the solar system, which fundamentally revolves around the presence of the Sun and its gravitational influence on the objects within its vicinity.