When you finally give up and throw out Aunt Edna's birthday card, where does it go? Out into the universe via the landfill. While you might be able to reduce chaos in one small location - like your desk - the very work you do creates more disorder for the rest of the universe. You have to do work to make order out of chaos and that is where a new kind of physics steps in.īack in the 1800s, scientists studying steam engines - of all things - tripped over a new fundamental law of nature: Nature always moves from order to disorder.
You have to sort through the piles and make new piles you have to decide which stuff to file and which stuff to throw out. To answer that question we have to go back to your messy desk.Īll those bills you need to pay, all those insurance forms you need to file, all those birthday letters you need to answer (you know, the one from Aunt Edna that's been sitting there for four months) - they represent chaos.Īnd to bring order to that mess you have to do work. So what, then, shoots the arrow of time forward? Why is the future different from the past? Or, putting it more personally, why do we have to die? We always move from past to future, from youth to old age, from birth to our inevitable end. We say something cruel to a loved one and we can never unsay it. We scramble eggs into omelets but can never unscramble them back into eggs. Of course, in life we have no problem telling the past from the future. There's just no difference between past and future in Newton's basic description of physics.
Make a movie of two billiard balls smacking into each other and Newton's laws can't tell you which direction the movie should run. Well, to be exact, they can't tell the direction of time. There was only one problem: Newton's laws can't tell time. Using these laws he could predict everything from the motion of the planets to the exact path of a bank shot in a game of pool. About 400 years ago, Isaac Newton figured out the basic laws governing matter and motion.