ABSTRACT
Why is it so easy to make something hotter and so much harder to make the same thing colder? You can rub your hands together and make them warmer. Why isn’t there a way to rub your hands together backwards, somehow, and make them get colder? Put some soup in a microwave oven, push a button, and the soup gets warmer. Will there ever be a cryogenic analog to the microwave oven? Will we ever be able to put the soda pop in a box, push a button, and in a few seconds, the pop gets colder? Such an idea is so foreign to us that not even the best science fiction writers have ever proposed such a device.
