A newly studied solar system breaks the usual planet pattern, raising fresh questions about how rocky and gas planets form.

All of our solar system’s planets are lining up in the night sky at once this week. This extraordinary celestial event will see the sky scattered with seven visible planets in what is known as a great ...

Add Yahoo as a preferred source to see more of our stories on Google. Are planets in the solar system that are closer to the Sun older than the ones further away? – Gavriel, age 10, Paducah, Kentucky ...

A planetary system 116 light-years from Earth has a peculiar pattern. It could flip the script on how planets form, scientists say.

Mercury is the smallest planet in our solar system. Explore its size, extreme temperatures, core structure, and comparison with Pluto.