Astronomers have long speculated about an unseen planet lurking in the solar system's outer edge. This hypothetical world, ...

See if you can put the planets in order based on the length (in hours) of their respective days going from longest to ...

Earth has four seasons, but do other planets in our solar system also have hot summer days and cold winter nights?

Our solar system may have a ninth planet after all, following the declassification of Pluto nearly two decades ago, ...

Caroline Delbert is a writer, avid reader, and contributing editor at Pop Mech. She's also an enthusiast of just about ...

Jupiter and Mars are on display during May evenings. It's your last chance to grab a good view of Jupiter before it drops out ...