A mathematician makes plans to travel backwards in time through a wormhole to a parallel universe when he can't even make it to Mars with the fastest rocket on hand today.

A mathematician believes that describing the speed of Mercury with equations amounts to science.

A mathematician says that an electromagnetic wave travels from Andromeda to your eye and that it also extends from Andromeda to your eye.

You can recognize a mathematical physicist because he always asks you for your credentials or lists his without you asking for them.