The Manhattan Project


The Manhattan Project combined America’s technological, industrial, scientific and financial might to produce the atomic bomb. The Manhattan Project brought together all the knowledge then known with regards to nuclear fission and culminated on July 16th, 1945, with an atomic bomb being exploded at Alamogordo in New Mexico. On August 6th and August 9th, two atomic bombs were used on Hiroshima and Nagasaki.


Part of the nuclear plant at Oak Ridge, ennesseeĀ 

The Manhattan Project was based at a 428,000-acre industrial complex in New Mexico; thousands of the West’s best scientists had worked on the project at one time or another. $2 billion had been spent – and no-one knew if the bomb would work, despite the input of some of the greatest scientific minds in the world. By mid-July, 1945, not even Robert Oppenheimer knew if ‘The Beast’ or ‘The Thing’ or ‘The Device’ (as the scientists variously nick-named the bomb) and he was the civilian leader of the project. Plutonium had not existed four years earlier and no-one was totally sure what reaction there would be when the bomb was detonated. There were varied opinions as to what might happen – some believed it would fail to explode. One scientist, the brilliant physicist Enrico Fermi, went to the other extreme and believed that it would set fire to the Earth’s atmosphere and create huge fires around the world.

On July 14th, two hemispheres of plutonium were moved from Los Alamos to the test site. The theory for an unparalled explosion on Earth was that the atoms in the plutonium would rid themselves of billions of neutrons which, in turn, would split other atoms thus releasing vast levels of energy in a chain reaction. When put together, the two hemispheres of plutonium were slightly larger than a tennis ball.

The omens for a successful outcome were not good. On July 15th, one of the so-called X-units (the trigger that would actually detonate the bomb) had blown its circuits for no known reason. This left the leaders of the project in a quandary – would the one in the bomb work?

Also as the bomb was being lifted up to the top of a detonation tower, it had fallen 50 feet and landed on mattresses. There was seemingly no damage – but no-one could see into the bomb, so no-one knew if the fall, despite the dampened landing, had actually damaged the core of the bomb.

On the night leading to the test, the test site itself was hit by a major electric storm. A lightening strike could have been disastrous – it would not have set off an atomic explosion but it could have seriously damaged the bomb that was set up in a tin shack at the top of a tower that was 103 feet high. Don Hornig, the creator of the X-unit, had been ordered by Oppenheimer to spend the night in the shack. He believed that the tower and shack, both rain-soaked, would act as an earth – but even the Harvard-educated scientist could not guarantee this.

To add to the project leaders woes, there was no constant wind direction and no-one could guarantee that the debris from a successful explosion would not blow into towns many miles away.

By all accounts, Robert Oppenheimer was a very nervous man as the time for the test explosion approached. The overall commander of the project, General Leslie Groves, was the opposite. Groves had total confidence in the Manhattan Project – a name he gave it as its first offices were in New York. He had spent the project’s set budget ($133 million) in just a few weeks – then continued spending. At one time, he had 100,000 people working under his command. Groves also had a dislike for scientists. He had Oppenheimer tailed by agents and tapped his phone. However, he also recognised that they had a vital part to play in the Manhattan Project.

In the early morning of July 16th, Groves took command of what was going on. Groves decided to delay the test. The original firing time had been 04.00 – but he wanted the weather to improve before he gave the go-ahead. A weather report indicated that the storm blighting the area was abate by dawn. At 04.00, the winds at Alamogordo started to veer north-east – the perfect direction, away from towns. The general weather pattern also improved and Groves, after discussing it with Oppenheimer, decided on a 05.30 firing. By this time, Don Hornig had been called down from the tower and returned to where the other scientists were.

The test director, Kenneth Bainbridge, armed the bomb via a series of switches. The countdown was done by Sam Allison. All those in the test area had been advised to wear welder’s goggles and to look away from the bomb when it exploded, even though the primary viewing station was 20 miles away.

“Lord, these affairs are hard on the heart.”

Oppenheimer, just before the explosion.

At 05.30, as planned, the first atomic explosion in history took place.

“It (the explosion) rose from the desert like a second sun, a searing, brilliant, expanding ball of fire, and it struck terror in everyone who witnessed it.Stephen Walker

It is estimated the at the instant of the explosion, the temperature at the core of the bomb was 60 million degrees centigrade and that the initial explosion was brighter than the sun. The bomb’s cloud rose at 5,000 feet a minute. It is said that the force of the bomb destroyed windows 120 miles away. The explosion was the equivalent of 22,000 tons of conventional explosives. To deliver the equivalent payload, 5,000 bombers would have been needed. The explosion had created a crater 1,200 feet in diameter and 25 feet deep. The brilliant light created by the explosion had been seen 180 miles away.

“My God, we’re going to drop that on a city?”Henry Linschitz, physicist on the Manhattan project

“We must keep this whole thing quiet.” (Groves)

“Sir, I think they heard it in five states.” (Unknown)


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