The Flesh of Physics

[n2doc]

January 26th, 2009 4:24 PM by Carl Zimmer in Life In Motion | 12

Our bodies are bunches of atoms, and like any rock or star or other bunch of atoms, we have to obey the laws of physics as we move. But each species obeys those same laws in its own way. My cat leaps onto my desk most mornings, his grace unblemished by the paper clips and computer cables he kicks onto the floor. A maple tree outside bends in the wind, a happy medium between flopping over and snapping in two. A hawk arrives at the tree and lands precisely on a branch. On their own, our eyes cannot tell us much about the different ways in which living things move. We can’t see the invisible vortices of air spiraling behind a hawk, the stresses experienced by different parts of the leaning maple, the thrust and torque generated by my cat as he rises into the air.

The first glimpse into this invisible world came in 1872. Leland Stanford, a railroad tycoon and the founder of Stanford University, spent a lot of time watching his race horses run. He was sure that when they trotted, there were moments when all four legs left the ground. Legend has it that he even bet $25,000 that they did.

Stanford paid a famed landscape photographer named Eadweard Muybridge to find out if he was right. Muybridge had horses trot down a path strung with threads connected to a row of cameras; when the horses snapped the threads, the cameras snapped the pictures. It took Muybridge years to perfect a shutter fast enough and film sensitive enough to capture the images (he also needed some time off to defend himself–successfully– against the charge that he had murdered his wife’s lover). But in 1877 he was finally able to give Stanford his answer. Horses do indeed bring all their legs off the ground during each cycle of a gallop. Later, Muybridge built contraptions that could display his pictures in quick succession. His moving pictures brought the horses back to life.

more:

http://blogs.discovermagazine.com/loom/2009/01/26/the-flesh-of-physics/