An explosion at ground level leaves a crater with a diameter that is proportional to the energy of the explosion raised to the power; an explosion of 1 megaton of TNT leaves a crater with a 1 km diameter. Below Lake Huron in Michigan there appears to be an ancient impact crater with a 50 km diameter.What was the kinetic energy associated with that impact, in terms of (a) megatons of TNT (1 megaton yields 4.2* 1015 J) and (b) Hiroshima bomb equivalents (13 kilotons of TNT each)? (Ancient meteorite or comet impacts may have significantly altered the climate, killing off the dinosaurs and other life-forms.)

An explosion at ground level leaves a crater with a diameter that is proportional to the energy of the explosion raised to the power; an explosion of 1 megaton of TNT leaves a crater with a 1 km diameter. Below Lake Huron in Michigan there appears to be an ancient impact crater with a 50 km diameter.What was the kinetic energy associated with that impact, in terms of (a) megatons of TNT (1 megaton yields 4.2* 1015 J) and (b) Hiroshima bomb equivalents (13 kilotons of TNT each)? (Ancient meteorite or comet impacts may have significantly altered the climate, killing off the dinosaurs and other life-forms.)