Countdowns

The more we learn about exoplanets, the more we realize the universe is stranger than we ever knew.

Getting excited about NASA's InSight lander touching down on Mars? We are, too! Here are some of the best books for young and old to read up about the Red Planet.

The Mercury program launched the first Americans into space, four on suborbital flights, and two who orbited the Earth.

Here's where to go to get your space shuttle fix in museums across the United States.

Earth has been sending probes to Mars for decades, and some missions are especially awe-inspiring.

Here are some of the more prominent Mars movies over the decades, to encourage you to keep exploring.

The four Galilean moons of Jupiter are Io, Europa, Callista and Ganymede.