New Clues About the Great Dying

Scientists know that approximately 250 million years something wiped out almost all the life on Earth; however, what exactly happened has remained a mystery - was it a volcano, asteroid strike, or something else? New evidence has been found in pockets of gas deep inside rocks that were formed during the time of the event. The gas contains higher than normal levels of a specific type of helium and argon which is more common in space, so something must have brought the material to Earth, probably an asteroid.