Unknown Interstellar Civilization

A thoughtful gleam flashed through He-El's eyes as he slowly rose into the air. His black cape billowed behind him as he crossed half the planet and arrived at a hole that led straight into the depths below. The hole was two kilometers wide. Looking down, it was lifeless and abyssal, its walls smooth and crystallized, with weak magnetic field readings. Standing at the edge of the sinkhole-like opening, He-El raised his head toward the gray-brown sky and had already guessed what had happened.