Know at least one type of balanced binary tree (and know how it's implemented): "Among balanced search trees, AVL and 2/3 trees are now passé and red-black trees seem to be more popular. A ...

When two stars orbit one another in such a way that one blocks the other's light each time it swings around, that's an ...

Disk galaxies, like our own Milky Way galaxy, commonly consist of both a thick and thin disk of stars—each with different ...