Antarctica averages minus 55°C at Vostok Station, yet a lake remains liquid beneath four kilometres of ice

Antarctica is the coldest continent on Earth, featuring a deadly combination of extreme temperatures, high elevation and ice-covered terrain. The Russian Vostok Station here averages minus 55°C and on July 21, 1983, it recorded the lowest reliably measured air temperature on Earth, −89.2°C.Yet sealed beneath the white ice sheets of the region is a hidden ocean-sized lake that challenges the human understanding of life's limits and nature's magic. About four kilometres beneath the station is not frozen bedrock but one of the largest lakes on the planet.Nature's anomalyLake Vostok is roughly 230 to 250 kilometres long and about 50 kilometres across at its widest pointLake Vostok is roughly 230 to 250 kilometres long and about 50 kilometres across at its widest point. Estimates of its exact area and depth vary as radar coverage and models improve, but its scale is comparable to Lake Ontario. It may hold substantially more water since much of its basin is deeper.The secret behind the lake staying liquid is a balance of ordinary physics operating at an unusual scale. The ice above insulates it from the surface, pressure lowers the melting point and a small but persistent flow of heat ri...