Can you imagine an object so huge that while its front end is touching the surface of the earth, its back end is about 35,000 feet in the air? That's the size of the meteor that collided with our planet 65 million years ago killing the dinosaurs and causing the biggest mass extinction in Earth's history. Now, can you imagine an object even bigger than that? Planetary scientists have found evidence of a killer meteor in Antartica that outsized the dinosaur mass-murderer.

The 300-mile-wide crater lies hidden more than a mile under East Antarctic Ice Sheet. Gravity measurements place it at about 250 million years old coinciding with the Permian-Triassic extinction. This was the period when almost all animal life on Earth died out paving the way for the Age of the Dinosaurs. The location of the impact also suggests it could have been responsible for the breakup of Gondwana, the supercontinent from which all continents today came from, by creating the tectonic rift that pushed Australia northward.

The Wilkes Land crater could be up to 30 miles wide, four or five times wider than the Chicxulub crater in the Yucatan peninsula. "This Wilkes Land impact is much bigger than the impact that killed the dinosaurs, and probably would have caused catastrophic damage at the time," according to Ralph von Frese, a professor of geological sciences at Ohio State University. Von Freese and colleague Laramie Potts led the team that discovered the crater.