Staring at the sun—a close (but safe) look at our home star Staring at the sun ... Free learning activities and videos about the solar system Free learning activities and videos about the ...

Though the planets are always “aligned,” seeing more than four in the sky is more uncommon. February’s lineup is a chance to ...

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 ...

This story appears in the July 2013 issue of National Geographic magazine ... and stared back at the birth of our solar system. They were stunned by what they saw. Scientists have long known ...