One fascinating idea that has been explored in several science fiction novels and films is the ability to transform a human being to live and breathe on an alien world without a space suit. But in the real world, could a man or woman be altered surgically or otherwise to survive on a planet such as Mars? In the 1976 Nebula Award-winning novel Man Plus, by Frederick Pohl, a human being is transformed into a cyborg to live on Mars. Its a rather disturbing look at how tinkering with our basic biology might isolate us from our essential humanity. Cyborg is short for cybernetics organism; its an organism that melds artificial and natural systems to create a new hybrid human. The term was coined in 1960 by scientists Manfred Clynes and Nathan Kline. You could say that a person today with an artificial heart, or even an artificial hip or some other metal or plastic body part, is a kind of cyborg. In Man Plus, the physical transformation of the fictional astronaut Roger Torraway into a cyborgactually an artificial martian is explored in great detail. Pohls literary imagination is firmly grounded in medical and biological fact extrapolated to the near future. While Torraway remains a human, he acquires alien insights as a new martian. Another unsettling look at building a human alien is the 1963 television program The Outer Limits: Architects of Fear. In this classic T.V. series episode, an astronautplayed by actor Robert Culpis surgically transformed into a bird-like, nitrogen breathing extraterrestrial Thetan. The scientists transforming the astronaut hope to fool a politically divided world into uniting against a common threat. While the idea of creating an extraterrestrial out of a human makes for great story telling, in reality building a human-E.T. hybrid is beyond the ability of modern scienceat least for now. Science-fiction writer Jack Cohen thinks the development of spines and skeletons is an evolutionary accident that is probably unique to Earth. But to adapt a bony human to live on Mars, it would have to survive near vacuum with a lot of shielding against lethal solar U.V. radiation. A human beings lung system would also have to be totally rebuilt to process the planets ultra-thin carbon dioxide atmosphere, in near vacuum, in order to survive. Simply stated, unprotected human physiology would suffer explosive decompression on the surface of Mars. But even if that problem were overcome, then a human-martian cyborg would have to endure the Red Planets vast range of temperatures from plus 60 degrees F down to minus 200 degrees F. New experimental technologies, such as liquid-breathing with perfluorocarbon chemicals as portrayed in the 1989 movie The Abyss, enable humans to live underwater without the aid of a conventional aqualung. But Mars is a very different, very alien place for humans compared to Earths oxygen-rich oceans. Of course, its always possible that unforeseen scientific breakthroughs will make it easier, and safer, for humans to adapt to living comfortably as biological extraterrestrials on distant worlds. But someday, we will travel to, and live on, other planets; well have to learn to adapt to, or perish on, these harsh and alien places. As author Ray Bradbury has said about NASAs current robot explorers on the Red Planet, There may be (the discovery of some) water flowing on Mars (today), but the important thing is the blood flowing in our veins and our hearts beating in our chests... you know damn well there's life on Mars. For Bradbury, humans already are the martians. Whats in the Sky: July 4: Earth is at aphelion on Independence Day. This means were at the most distant point from the Sun in 2008. We are just more than a million miles farther from the Sun than the usual 93 million miles. July 5: Mars and Saturn are near each other, low in the west, near the Moon after sunset. Lou Varricchio, M.Sc., lives in Vermont. A former NASA senior science writer, he is involved with the NASA/JPL Solar System, Ambassador program in Vermont.