Compare the physical characteristics of the sun to the planets. Compare and contrast the physical characteristics of the inner planets to those of the outer planets, the gas giants. Planets and moons are made of a variety of elements and exist in many sizes. Inner planets are small and rocky, while the outer planets are large and gaseous. The solar system is also home to asteroids and visiting comets.
Comets are balls of ice and rock, and they travel far out beyond the planets.
The asteroid belt is found between the orbits of Mars and Jupiter. Most of the planets in our solar system have atmospheres, but most moons do not. Generally, the bigger something is, the more gravity is has. Instead, its atmosphere thickens and changes gradually with depth due to heat, temperature, and chemical composition. A large body that orbits the sun or another star and does not shine in visible light, but reflects light.