Are planets in the solar system that are closer to the Sun older than the ones further away? – Gavriel, age 10, Paducah, Kentucky A cloud of collapsing gas created our Sun, the first thing to form in ...

The Sun's formation caused temperature differences in the surrounding disk of gas and dust. Inner, hotter regions formed rocky planets from less volatile elements. Outer, colder regions allowed ...

Pluto was reclassified as a dwarf planet in 2006. Our solar system may have a ninth planet after all, researchers say. The possibility that an additional planet may be hidden far into the solar system ...

The giant planets weren't always where we find them today. Jupiter, Saturn, Uranus and Neptune formed in a more compact ...

Our solar system is a smashing success. A new study suggests that from its earliest period — even before the last of its nebular gas had been consumed — Earth’s solar system and its planets looked ...

(The Conversation is an independent and nonprofit source of news, analysis and commentary from academic experts.) Curious Kids is a series for children of all ages. If you have a question you’d like ...