Many of us know that a 3-D model of the Earth, moon, sun and planets used to explain the way these bodies work is called a planetarium. But few are familiar with a tellurian (tellurium), a mechanical ...

If our solar system seems stable, it's because our short lifespans make it seem that way. Earth revolves, night follows day, the moon moves through light and shadow, and the sun hangs in the sky. But ...