Staring at the sun—a close (but safe) look at our home star ... a new idea to keep kids entertained? Try stargazing. Free learning activities and videos about the solar system Free learning ...

With a radius of 3,959 miles, Earth is the fifth largest planet in our solar system, and it's the only one known for sure to have liquid water on its surface. Earth is also unique in terms of ...

Watch this video to find out more about the Earth, planets in our Solar System and other planets far off in outer space. From up here on the International Space Station I get a great view of Earth.