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Updated: Aug 1, 2023

The practically pre-ordained MOVIE OF THE YEAR opens this Friday. Here's some useful background info.

Did your Grumpy Old Mansplainer actually split atoms as a youngster? Sorry, the answer is classified. (Yes, this really is an actual toy from the 1950's.) Here are some relevant questions we CAN answer

The avant-garde German band KRAFTWERK (Rock & Roll Hall of Fame class of 2021) was far more influential than most people realize. RADIOACTIVITY is one of my favorite music videos of all time.


Atoms that emit or "radiate" sub-atomic particles and/or discrete packets of pure energy (called photons) are considered radioactive. But wait, there's more... WAY more.

Some atoms, both naturally-occurring and man-made, decompose either spontaneously or with a little external assistance into smaller atoms in a process known as "fission." In doing so, they simultaneously release neutrons and also pure energy in the form of electromagnetic radiation, a.k.a. EMR. (Not as scary as it sounds; visible light is EMR... as are television and radio signals, x-rays, ultraviolet light, and infrared heat.) Other forms of radiation beyond the scope of the OPPENHEIMER movie entail emissions of tiny charged particles such as electrons or positrons (Beta Radiation) or much heavier Helium nuclei (Alpha Radiation.)

Radioactivity is more common than one might offhandedly surmise, as in glow-in-the-dark clocks and watches and nuclear medicine. One increasingly common example of the latter is the PET-Scan, wherein cancer patients are injected with harmlessly radioactive sugar compounds that are especially drawn to cancerous cells and then reveal their locations in the patient's body via their detectable emissions of positrons. Of course, nuclear-powered electrical generation and nuclear bombs involve radioactivity far more powerful that that used for watch faces and medical procedures. (Click HERE for the U.S. Department of Energy's official explanation of radioactivity.)


For Albert Einstein, 1905 was a really good year... a real Annus Mirabilis in Latin. He published four seminal scientific articles that year (some argue FIVE) that contributed mightily to mankind's understanding of both the inner atom and outer space. One of these articles introduced what has perhaps become the world's most famous equation:

E is energy; m is mass; and c is the speed of light, 300,000 kilometers per second. Because matter is converted to energy in nuclear reactions, this equation describes the fundamental basis for nuclear energy... and, BTW, is not the same as Einstein's theory of relativity.

The upshot of this equation is that a really tiny amount of matter (OR just mass in the form of nuclear bonds... it's complicated) can be converted into a tremendous amount of energy... the nuclear energy that produces electricity in nuclear power plants as well as the destructive energy released by a nuclear bomb. The very first such controlled laboratory conversion of matter/mass into energy via fission (splitting atoms) took place in a Germany in 1938. (Click HERE for details.)


A lot of different ways, but here's an example directly related to the OPPENHEIMER movie– gather a radioactive material (say, a particular formulation of Uranium known as U-235) in sufficient quantity and close enough proximity, and it not only emits pure energy (in this case in the form of gamma rays, the most powerful form of EMR) but also a pair or more of neutrons that act as "bullets" as they strike other nearby radioactive atoms and cause them to similarly split and emit both pure energy (from the conversion of a bit of the mass) and neutrons that shoot forth and split other atoms. When this happens over and over, we call it a nuclear chain reaction.

This is where it gets tricky. If our U-235 is of insufficient quantity and/or too physically dispersed, our nuclear reaction will be subcritical, i.e. not a chain reaction, not self-sustaining. At the other end of the spectrum, a sufficiently dense and voluminous accumulation of U-235 goes supercritical; that is, the chain reaction so rapidly accelerates that a tremendous amount of radiation is quickly released and, under specially-engineered circumstances, a powerful explosion might well occur. Between these two extremes, a chain reaction held in perfect balance is called critical... neither accelerating nor slowing its pace and thereby delivering a steady stream of radiation... energy that can boil water and thus drive electricity-generating steam turbines. Nuclear power plants use various methods to maintain this critical equilibrium in order to produce a steady stream of usable energy. As some (but not all) of history's nuclear power plant disasters attest, critical nuclear reactions can quickly turn into out-of-control supercritical reactions. (I recently described nuclear-generated electricity to a friend as akin to "heating your house with TNT.")

One big takeaway? In 1942 it was actually simpler to make a supercritical atomic bomb that went from zero to Armageddon in mere nanoseconds than it was to build a controlled critical-reaction nuclear power plant.

So, back to the early years of World War II...


Kinda, sorta... however, the antisemitic tide that swept Europe in the 1930's drove a lot of Jewish physicists across the Atlantic and into the arms (and university science departments) of the Americans. (For the record, nearly all of the prominent theoretical physicists of the early 1900's were Jewish.) Hitler being Hitler, the 20th century's wave of advances in theoretical physics– relativity, mass-energy equivalence, quantum mechanics, etc.– was officially denounced and ridiculed by the Third Reich as "Jewish Physics," and accordingly the pursuit of nuclear weaponry was given less emphasis by the Germans than was their development of jet aircraft and rocketry.

But we Americans had no way of knowing that in the early stages of World War II... all we knew for certain was that A.) Germany had produced that sustained nuclear reaction back in 1938; and B.) that a top-notch nuclear physicist named Werner Heisenberg was still in Germany and likely working on a German A-bomb.

Enter the Manhattan Project... and the brilliant American-born scientist named J. Robert Oppenheimer. For the rest of this story, you'll have to join me and millions of others as we watch the movie.

OPPENHEIMER opens in theaters Friday, July 21.

* * * * * * *


First, a historical note– this movie is concerned with the development of fission bombs, a.k.a. atomic bombs or A-bombs. In contrast, Hydrogen bombs, a.k.a. thermonuclear bombs or H-bombs, are fusion bombs, i.e. with reactions that join two very small atoms into one slightly larger atom in such a way that also converts matter into energy. Fusion is the reaction that keeps our sun shining warmly upon us earthlings from 93 million miles away... and, in the H-bomb, produces a blast many thousand times more powerful than that of a fission bomb.

Since it takes a fission bomb to light up a fusion bomb– and there was, of course, a world war in progress– Oppenheimer and his boys busied themselves with creating fission weapons. H-bombs would enter the picture a few years later.

Yes, the OSS (the precursor of the CIA) really did send a former Boston Red Sox catcher to find out if Werner Heisenberg was actually working on an A-bomb... and if so, with orders to kill him. Check out the story of the man named Moe Berg.

Although the basics of Nuclear Detonation 101 and the actual designs of nuclear weapons are widely available online, out of prudence (and, frankly, fear of Big Brother) I've declined to include such information and any detailed discussion thereof on such a public site. If you're willing to risk having your google search flagged, all of this information is out there.

That being said, there is plenty of info out there about nuclear physics and nuclear power plants that likely won't attract so much FBI interest if you are interested enough to google it in depth. In particular, I find the underlying physics of the various plant disasters well worth studying.

There are lots of things that can go wrong in a nuclear power plant, not all of which involve runaway CHINA SYNDROME-like nuclear meltdowns. Indeed, only a small number of reactor accidents are thought to have achieved super-criticality: Chernobyl #4, the U.S. Army's SL-1, and the Soviet submarine K-431.

Although the Three Mile Island incident didn't involve a runaway reaction, it certainly deserved an Oscar for worst timing. When THE CHINA SYNDROME movie was first released on 16 March 1979, nuclear power executives immediately lambasted the picture as "sheer fiction" and a "character assassination of an entire industry." Exactly twelve days later, the world's eyes turned to central Pennsylvania as the Three Mile Island nuclear accident unfolded.

Should you opt to delve further into this branch of science, it is worth noting an important distinction that I glossed over in the body of this essay: Among supercritical reactions, there's delayed-neutron criticality or super-criticality, and then there's prompt-neutron criticality or super-criticality. That's because when a large atom (like, say, Plutonium) divides, it gives off gamma ray energy AND two (or more) neutrons AND two smaller offspring atoms... atoms which themselves divide AND emit neutrons... and a chain reaction perpetrated solely by neutrons from the parent Plutonium atom happens a little more promptly (get it?) than a reaction requiring the assistance of neutrons from Plutonium's offspring atoms. Truth be told, the difference is measured in mere nanoseconds, but that minuscule difference nonetheless makes a HUGE difference when it comes to the destructive power of a nuclear detonation.

Also worth noting:

ALL nuclear power plants run on fission reactions. While the technological journey from A-bombs to peaceful fission power plants took only seven years, the quest for peaceful fusion power remains unfulfilled some seven decades after the first H-bomb detonation.

And finally...

Way back in 1984 I got a visit from a secret service agent who came to question me about an old girlfriend who was taking a job in the nuclear industry that required a very high security clearance. I shall always recall fondly her family's extraordinary kindness and generosity, and she and I keep in touch to this day. BIG thanks to S. and her sportingly gracious husband M. (a fellow nuclear engineer) for their assistance with this essay.

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