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 ...

The discovery of what might be our solar system’s 10th planet could change the way astronomers label the objects they find in the skies. The key question, still unresolved: Just what is a pla… ...

When I need to remember the order of the planets I recite the phrase I learned in school: My Very Excellent Mother Just Served Us Nine… and then I stumble just as I get to “Pizzas.”. Because ...

This article was originally featured on The Conversation. Are planets in the solar system that are closer to the Sun older than the ones further away? – Gavriel, age 10, Paducah, Kentucky A ...