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 ...

However, we actually have six in our Solar System. Pluto, Ceres, Makemake, Haumea, and Eris were the only five that we knew about up until very recently. Ceres is in the asteroid belt between Mars ...

After a decade-long search, some scientists say a growing number of clues point to the existence of a hidden planet in the Kuiper Belt beyond Neptune — and they may soon have the opportunity to find ...

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 ...

Since its discovery in 1930, until 2006, Pluto was counted as the ninth planet in the solar system. In 2006, the International Astronomical Union reclassified it as a ‘dwarf planet’, and our ...