A mirage in the Mojave desert

What causes a mirage in the road?

... refractive index from the air around it. Air also has its own refractive index which depends on the temperature of the ...

The Hitchhiker's Guide to the Galaxy

Why is 42 "the answer to the universe"?

... did they like the number as well or do they have their own magic ‘nice to say’ number? James - So, I know that ...