Astronomers recently detected a stray quasi-moon in our planet’s orbit, but it's hardly the first stowaway to hang out around ...

At a young age, we're told how the sun warms Earth and makes life possible. That idea sticks with most of us for life. But ...

What is the difference between a moon and a planet? Trick question! According to scientific definitions, there often isn’t much of a difference at all. That might seem counterintuitive, but it’s true.

Uranus is the only planet that rotates sideways with a 98-degree tilt. Learn why Uranus spins this way, how its seasons last ...