icrobes have been found in almost every type of environment. Some thrive in subzero Arctic ice, while others live in boiling undersea volcanoes. Bacteria have been found inside oil-drilling cores pulled from more than a thousand feet down in the earth's crust, and it has been estimated that there may be as much as 100 trillion tons of bacteria deep beneath the surface of the earth. If all the subterranean microbes were brought to the surface, they would cover the planet with a layer five feet deep. Microbes have been discovered six miles beneath the Pacific Ocean, where the pressure is equivalent to being squashed by fifty jumbo jets, as well as nineteen miles out in space.