Antarctica is a continent layered by a sheet of ice that is two miles thick in some places. There is so much ice that the weight of it has sunk the continent substantially, resulting in an average height below sea level; at some locations it is below 1.5 miles (far lower than the Dead Sea), with miles of ice stacked on top of the ground.
This makes for an interesting topography of subglacial canyons and lakes. Denman Glacier, the deepest point on earth, is an ice-filled canyon that stretches 11,500 feet below sea level. For comparison, the Grand Canyon is only 5,000 feet deep. The subglacial Lake Vistok would be the 10th largest lake in the world if visible on the surface. Ice cores from the two mile deep lake have been taken that reveal a potential ego system with microscopic life.
That life can survive in such extreme environments as a subglacial lake at the south Pole buried under 2 miles of ice supports the idea that other ice planets and moons may harbor it. One example is Enceladus, a moon of Saturn, which globally iced over. Despite being more than twice as far from the sun as Earth, it may have environmental conditions that favor biogenesis. The more we can learn about these buried ego systems, the more we can infer that perhaps sunlight and oxygen aren't so fundamental to life after all.
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