This week, scientists in the international Ocean Drilling Program announced that they had found living organisms over 800 meters below the ocean bottom, trapped inside sedimentary rocks over 15 million years old. Last month, scientists from the University of Washington and the American Museum of Natural History managed to lift several huge, hot sections of sulfide chimneys, the smokestack-like mineral features that form around deep-sea hydrothermal vents. And in June, researchers at Montana State University and elsewhere released findings about organisms thriving in the permanent ice layer in lakes in an Antarctic desert - organisms which somehow manage to live happy, full lives despite rarely seeing temperatures above -20 Celsius.

Researchers are eagerly studying each new find, and are using their findings to learn more about the origins of life on Earth, about current ecosystems on the planet, and about the possibilities for life on other worlds. Other scientists, known as bioprospectors, are looking at the new life forms as the possible basis for business. The enzymes needed for the polymerase chain reaction (PCR) technique that allows the rapid duplication of DNA segments for study were found by studying bacteria living in hot springs. Now companies are scouring the globe looking for other new life forms that might prove useful as well.

Is there anywhere on Earth that life can't live? On this hour of Science Friday, we'll be looking at life in extreme environments, from the cold and dry to the very warm and wet, and places in between.

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