What Exactly Happened To Hal In 2001: A Space Odyssey?

Having now read the book version of 2001: A Space Odyssey, I can now decisively answer a question that always bugged me after watching the the movie version, which was: what the hell happened to Hal? Why did he lose it and try to kill all the astronauts?

Why Salt Was So Important Throughout History

These days, salt is so abundant that it’s easy to take it for granted. If you had lived in any other time in history, though, chances are that your relationship with salt would have been dramatically different.