When I was a kid, there were nine planets. Now we know of thousands! But that includes exoplanets, alien worlds that orbit alien suns. Only eight planets call our solar system home. Or there might ...

All of our solar system’s planets are lining 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 ...

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 cloud of ...

An object eight times the mass of Jupiter may have swooped around the sun, coming superclose to Mars' present-day orbit before shoving four of the solar system's planets onto a different course. When ...

Lucas Brefka receives funding from a NASA Exoplanet Research Program grant. Christopher Palma does not work for, consult, own shares in or receive funding from any company or organization that would ...