It was on this day in 1945 that the first atomic bomb was exploded at 5:30 a.m., one hundred and twenty miles south of Albuquerque, New Mexico. It was the end result of the Manhattan Project, which had started in 1939. The bomb contained a ball of plutonium about the size of a baseball, surrounded by a ring of uranium and a series of detonators. Its main pieces were placed on the backseat of an army jeep and driven to the test site, where the bomb was assembled and positioned at the top of a hundred-foot steel tower for the test explosion.
At 2:00 a.m. on this day in 1945, a thunderstorm blew in from the Gulf of Mexico. The men assembling the bomb had to do so in the midst of a lightning storm, wondering what would happen if lightning struck the tower. But the weather cleared up just before dawn. They started the countdown fifteen seconds before 5:30 a.m. The physicists and military men watched from about 10,000 yards away. They all wore Welder’s glasses and suntan lotion.
One of the physicists who was there that day said, “We were lying there, very tense, in the early dawn, and there were just a few streaks of gold in the east; you could see your neighbor very dimly. … Suddenly, there was an enormous flash of light, the brightest light I have ever seen … it bored its way right through you. It was a vision which was seen with more than the eye. It was seen to last forever. … There was an enormous ball of fire which grew and grew and it rolled as it grew; it went up into the air, in yellow flashes and into scarlet and green. It looked menacing. It seemed to come toward one.”
The ball of fire rose rapidly, releasing four times the heat of the interior of the sun, followed by a mushroom cloud that extended forty thousand feet into the sky. Tests showed that it had released energy equal to 21,000 tons of TNT. The burst of light was so bright that it lit up the moon. An army captain in Albuquerque who knew about the test could see the explosion from his hotel room, more than a hundred miles away.
Later, when the scientists went to examine the site of the explosion, they found a crater in the ground 1200 feet in diameter. The ground was covered with a green, glassy substance, which was actually sand that had been fused into glass by the heat.
At the time, the military announced that an ammunitions dump had exploded, and a few weeks later the atom bomb was dropped on Hiroshima.
Source: The Writer’s Almanac from American Public Media (2006).