A recent discovery could explain why the Leaning Tower of Pisa is shaped like a lighthouse. Watch a new episode of #Unearthed tonight at 9p ET only on Science Channel and on SCI go. | Science Channel

Between 1589-1592, Galileo's experiments with gravity from the top of Leaning Tower of Pisa became stuff of legend and are commonly used in school textbooks today to help children understand the relation between mass and gravity. But is it possible to disprove Galileo, and have two objects of different mass descend at the same speed? It can be done, if one has the scientific resources of NASA! Watch 'Human Universe' to find out the story behind this surprising experiment, every night at 8 PM. #F