A Stranger is Watching

How and where did life begin? Is it a chemical fluke, unique to Earth, or the product of intriguingly bio-friendly laws governing the entire universe? In his latest far-reaching book, "The Fifth Miracle," internationally acclaimed physicist and writer Paul Davies confronts one of science's great outstanding mysteries -- the origin of life. <P> Davies shows how new research hints that the crucible of life lay deep within Earth's hot crust, and not in a "warm little pond," as first suggested by Charles Darwin. Bizarre microbes discovered dwelling in the underworld and around submarine volcanic vents are thought to be living fossils. This discovery has transformed scientists' expectations for life on Mars and elsewhere in the universe. Davies stresses the key role that the bombardment of the planets by giant comets and asteroids has played in the origin and evolution of life, arguing that these "deep impacts" delivered the raw material for biology, but also kept life confined to its subterraneanhaven for millions of years. <P> Recently, scientists have uncovered tantalizing clues that life may have existed and may still exist -- elsewhe