5 The icy wastelands of Antarctica are infamously barren and inhospitable, making research very difficult It stretches for a distance of 151 miles across and has a maximum depth of about 848 metres. Some researchers believe it is the remains of a truly massive asteroid which was more than twice the size of the Chicxulub space rock which wiped out the dinosaurs. If this explanation is true, it could mean this killer asteroid caused the Permian?"Triassic extinction event which killed 96 percent of Earth's sea creatures and up to 70 percent of the vertebrate organisms living on land.