Nine planets of very different size, composition, and surface features move around the sun in nearly circular orbits. Some planets have a variety of moons and even flat rings of rock and ice particles orbiting around them. Some of these planets and moons show evidence of geologic activity. The earth is orbited by one moon, many artificial satellites, and debris.
For Grades: 9-12
Learning Goal 4
Mathematical models and computer simulations are used in studying evidence from many sources in order to form a scientific account of the universe.
For Grades: 6-8
Learning Goal 5
The moon's orbit around the earth once in about 28 days changes what part of the moon is lighted by the sun and how much of that part can be seen from the earth- the phases of the moon.