Each week, we push our trash to the curb, and it seemingly disappears. But where does it all go: the spent cartons of milk, the computer keyboard fried by spilled coffee, those empty dog food cans?

A team of researchers at the Massachusetts Institute of Technology decided to find out. In 2009, they began attaching transmitter chips to thousands of pieces of ordinary garbage. They tossed this "smart trash" into the bin, sat back and watched the tortuous, disturbing path that our garbage often takes: the meanderings...