Some theoretical scientists -- and science-fiction writers -- will tell you it's only a matter of time before our minds are freed from the ravages of our deteriorating bodies; we'll be downloaded into machines, and live on like that forever ... barring any unforeseen hard drive wipes or data corruptions. Sure, it sounds a little far-fetched right now, but when you look at what's coming out of robotics and prosthetics labs today, it's tough to rule our such Asimovian scenarios. Take, for instance, the new rocket-powered prosthetic arm being developed by mechanical engineers at Vanderbilt right now:

"¢ It weighs about as much as a human arm, and for the first time in prosthetics, it can also lift about as much as a human arm, easily curling 20-25 lbs. That makes it about ten times stronger than other robotic arms.
"¢ Because batteries powerful enough to power such a device quickly become too heavy, the team replaced them with a "miniaturized [version of the] monopropellant rocket motor system that is used by the space shuttle for maneuvering in orbit." It's "about the size of a pencil and contains a special catalyst that causes hydrogen peroxide to burn. When hydrogen peroxide burns, it produces pure steam. The steam is used to open and close a series of valves."
"¢ Naturally, a steam-powered arm gets a little hot. So rather than outfitting it with traditional steam vents -- which could burn the user -- the heat is vented through a porous cover, ending up as a small amount of sweat-like moisture on the arm itself.

While I'm not exactly looking for a lion to chew my arm of so I can finally get one of those babies for myself, it does sound functional enough that I could imagine sporting one without feeling like a circus sideshow -- especially since they're developing technology right now which would control the arm via nerves in your body or brain. Artificial hearts and joints are already common, and now limbs are advancing by leaps and bounds. Once we begin solving some of those degenerative brain diseases that plague millions of the elderly -- Parkinson's, Alzheimers, dementia and so on -- what will stop us from just replacing whatever's broken in ourselves until we're more robot than human?