THE cloud itself was kind of rough," wrote a sailor, "yet it looked smooth something like a cauliflower." Poets were not invited to Operation Ivy to witness the dawn of the hydrogen age, so it was as a cauliflower that the H-bomb's first cloud was trademarked last week a realistic if nonpoetic progression in vegetables from the A-bomb's first mushroom.
Ivy's explosion broke the stillness of a mid-Pacific morning on Nov. 1, 1952; at 7:15 a.m., observers on ships and planes 50 miles away watched an enormous deep-orange fireball blaze up in the distance. Then it rose to the stratosphere,...