Explore the mythology, structure, observational history, gravitational force, and orbit of Earth's Moon.

Resource explores the solar system, with an in depth discussion of each of the planets and their properties.

In ancient times only five planets were known: Mercury, Venus, Mars, Jupiter, and Saturn. Learn about Greek astronomer Ptolemy's theory for the solar system that was to survive for fourteen centuries.

Kids learn about the timeline of the history of space exploration including early astronomy, astronauts, spacecraft, planets, and the Moon.

The planet Mercury is profiled with information about its size, mass, atmosphere, length of day, and the like. Features include interactive activities and learning exercises.

Kids learn about the ice giant planet Uranus of the Solar System including fun facts, mass, day, year, and distance from the Sun. Astronomy for kids and teachers.

Kids learn about the planet Venus of the Solar System including fun facts, mass, day, year, and distance from the Sun. Astronomy for kids and teachers.

View pictures and links to more information about Jupiter's moon Europa. Links are also provided throughout for additional information on related subjects.

Find out about all the planets and other solar system characteristics in this colorful, illustrated tutorial on our neighborhood in space.

An article explaining how the Greeks were able to use their science and mathematics to predict where astronomical objects such as the Planets could be found in the nighttime sky even though their underlying premise was that the earth did...

This comprehensive site delves into other aspects of our solar system besides the planets and the sun. Click on the topics on the right like solar winds, the heliosphere, the heliopause, asteroids, comets, and more.

Kids learn about the planet Jupiter of the Solar System including fun facts, mass, day, year, and distance from the Sun. Astronomy for kids and teachers.

Kids learn about the planet Mars of the Solar System including fun facts, mass, day, year, and distance from the Sun. Astronomy for kids and teachers.

Kids learn about the planet Mercury of the Solar System including fun facts, mass, day, year, and distance from the Sun. Astronomy for kids and teachers.

Kids learn about the ice giant planet Neptune of the Solar System including fun facts, mass, day, year, and distance from the Sun. Astronomy for kids and teachers.

This site from the University of Arizona provides a background of Ptolemy's profound influence in the areas of astronomy, geography, and cartography. Includes good pictures and related links.

All About Space profiles the planet Venus with information about its size, mass, atmosphere, length of day, and the like. Features include interactive activities and learning exercises.

A simulation illustrating Ptolemy's geometrical system of explaining the varying speeds and directions of the planets, sun, and moon.

This site from Open Source Physics offers a file with a simulation of Kepler's theory of planetary motion, tested with the Earth rotating around the sun and another planet of the user's choosing. The download requires Java.

Read about the vital statistics, composition, and other facts about our home planet, Earth.

How much would you weigh on Mars? Learn this information and other cool facts about the red planet, Mars.

A NASA scientist, Dr. Sten Odenwald, answers many students' questions. Topics include planets, galaxies, black holes, the origin of the universe, and common misconceptions about space.

An easy-to-read description and history of Ptolemy's geocentric model of the universe. Geocentric means that Ptolemy believed the Earth was the center of the universe.

A wealth of facts await you on this complete site. Topics include size, mass and gravity, length of day, orbit, distance from the sun, and more. A coloring page, quiz, fill-in-the-blanks activity, and interactive puzzle will challenge...