And we live in a time when we will soon be able to look for life outside our own solar system. In 1977, a small submarine dubbed Alvin descended to about 8,000 feet near the Galapagos Islands where the sea floor was cracking under the pressure of volcanic activity. As the searchlights scanned the sea floor, they revealed among the barren expanses dense communities of life clustered around vents spewing lava-heated water and debris into the frigid surroundings. Researchers were astonished to discover the food chain was built on previously unknown forms of heat-loving microbes. These organisms thrive in the inky, rolling clouds of 600-degree water and sulfur.
Temperatures can go only so high before biochemistry breaks down.
But at the limits, some microbes, dubbed extremophiles, thrive. Many scientists now regard deep sea thermal vents as a dark window into the primordial conditions that gave rise to life billions of years ago, when Earth was far less hospitable. This model has potentially far reaching implications for virtually all theories about life formation. Formulated largely by Cornell University astronomer Thomas Gold, the theory proposes that life arose not near the surface of the early seas, where it drew energy from sunlight, but from primitive microbes thriving in the depths of the planet, feeding on its chemical energy. The Deep Hot Biosphere .