among the largest physical structures on the planet
เข้าดู: 4 ตอบ: 0 13/05/22 14:05
In these extreme conditions, the granite eventually ceased to be drillable – it was behaving more like plastic than rock. The experiment was halted, and no one has managed to pass the crust's threshold to this day. The only remaining hint of the Kola borehole's existence is a rusty metal cap embedded in the ground.