He wasn't wrong—the sun is 99.8 percent of the mass of the solar system. But what is that giant ball of fire in the sky? How ...

Though costly to implement, solar energy offers a clean, renewable source of power. 3 min read Solar energy is the technology used to harness the sun's energy and make it useable. As of 2011 ...

Need a new idea to keep kids entertained? Try stargazing. Free learning activities and videos about the solar system Free learning activities and videos about the solar system Free learning ...