This is totally cool: an animated simulator that lets you make model solar systems! It's put together by the PhET Interactive Simulations group at -- hey! -- the University of Colorado at Boulder. All ...

Everyone knows that as mere Earth-dwellers, our home planet is but a pale blue dot when compared to other celestial bodies. Even our nearby planets quickly become magnitudes larger than ourselves, and ...

It's hard to understand just how truly big something is without seeing it, or at least having something to compare it to. Understanding how large objects can be in space is a common problem for some ...