The idea of a moon having its own moon sounds strange but fascinating. People often wonder if a smaller object could orbit around a regular moon, just like moons orbit planets. Scientists have ...

So far, humanity has yet to find its first "exomoon"—a moon orbiting a planet outside of the solar system. But that hasn't ...

Free-floating, planetary-mass objects that are just drifting carefree through the galaxy, untethered and starless, appear to be able to generate their own systems of moons, like a planetary system on ...

Could the icy moons of our solar system hold life beyond our planet? Keith Cooper looks at how planetary scientists plan to ...