Five Hundred Hiroshimas

At dawn on March 1, a Marine corporal on lonely Kwajalein saw an awesome sight. "All of a sudden," he wrote his mother, "the sky lighted up, a bright orange, and remained that way for what seemed like a couple of minutes . . . We heard very loud rumblings that sounded like thunder. Then the whole barracks began shaking as if there had been an earthquake. This was followed by a very high wind." In another letter, two days later, the corporal reported that two U.S. destroyers pulled into Kwajalein with victims of atomic radiation.

Man's Greatest Explosion. What the corporal saw and reported from his own perch was the result of the biggest explosion ever set off by man. It happened several hundred miles away from Kwajalein, somewhere in the U.S. proving ground in the Marshall Islands. In a precautionary rehearsal of a formal test shot from an Air Force bomber that will take place sometime in the next two weeks, U.S. scientists had exploded a thermonuclear device atop a tower. The force of the blast completely surprised them.

Calculations of the explosion's energy and effect are incomplete, but they were so great that the Atomic Energy Commission was forced to reclassify the previous tower shot (Nov. 1, 1952) as a misfire.

The details of that misfire are awesome enough. Items:

P: Its fireball measured 28 miles in diameter.

P: Its force was calculated at five megatons, i.e., equal to 5,000,000 tons of TNT or 250 times the force of the Hiroshima atomic bomb.

P: Its mushroom cloud climbed 90,000 feet, into the stratosphere, and a fast transport plane carrying an Air Force general and an Atomic Energy Commissioner at 30,000 ft., 50 miles away, had to turn and run to avoid being caught under the lip of the mushroom.

A String of Salutes. The test of last fortnight makes all its predecessors, including the 1952 shot, look like a string of one-inch salutes. The force of the explosion probably exceeded ten megatons (500 Hiroshimas). It sent a radioactive cloud billowing to a height that may have exceeded 20 miles. In the thin air of the stratosphere, it seems likely, the cloud slumped over like water tossed from a bucket.

Twenty-eight U.S. observers and 236 natives of local islands had been evacuated to what had been considered a completely safe refuge, but the unpredicted "fall-out" showered them with radioactive particles. Their exposure to radiation was ten times greater than scientists deem safe, but the AEC was reassuring. "There were no burns," said a commission announcement. "All are reported well. After completion of the atomic tests, they will be returned to their homes."

The 1954 blast upset plans for the formal test shot, which will be witnessed by the AEC, the Joint Congressional Atomic Energy Committee, and Dr. Edward Teller, the scientist principally responsible for the thermonuclear weapon. While scientists feverishly recalculated their data and tried to explain the unexpected force of the big blast, the formal test was postponed a few days. That test, in which a thermonuclear device will be dropped from the bays of a B-36 on the shrouds of a huge parachute (to give the plane time to get out of the way), is expected to duplicate the March 1 explosion.

The prospect sobered the Government officials who will witness the shot. Last week, as he prepared to leave for the Pacific, AEC Chairman Lewis Strauss said goodbye to a reporter: "I'll see you when I get back--if I get back."

This file is automatically generated by a robot program, so reader's discretion is required.