October 23, 2009
Written by: Jessica Behnham
EVERYONE knows that the dinosaurs were exterminated when an asteroid hit what is now Mexico about 65m years ago. The crater is there. It is 180km (110 miles) in diameter. It was formed in a 100m-megatonne explosion by an object about 10km across. The ejecta from the impact are found all over the world. The potassium-argon radioactive dating method shows the crater was created within a gnat’s whisker of the extinction. Calculations suggest that the “nuclear winter” from the impact would have lasted years. Plants would have stopped photosynthesising. Animals would have starved to death. Case closed.
Well, it now seems possible that everyone was wrong. The Chicxulub crater, as it is known, may have been a mere aperitif. According to Sankar Chatterjee of Texas Tech University, the main course was served later. Dr Chatterjee has found a bigger crater—much bigger—in India. His is 500km across. The explosion that caused it may have been 100 times the size of the one that created Chicxulub. He calls it Shiva, after the Indian deity of destruction.