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Measuring the Unthinkable December 8, 2010

Posted by Lofty Ambitions in Science.
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Photo by Noir

In the spring of 1989, a couple of Midwestern college students might have been forgiven for believing that the Cold War was still being waged with all of its chillingly vibrant madness. The newly minted 41st President seemed in no hurry to break precedent with the velvet-concealing-hammer rhetoric of his predecessor. The fall of Die Berliner Mauer and the election of Václav Havel—and the later emergence of the Czech Republic—was still months away. The political zeitgeist, the calculus of international relations, could easily lead the laity to wonder how and when it might all end.

Sometime during that springtime, Knox College conducted a hiring search for a new Physics professor. As a small-world aside, the eventual winner of that job search, Dr. Phillip Mansfield, would later become an acquaintance of a friend, Dethe Elza, whom we wouldn’t “friend” until years later at Ohio University. The events—Dr. Mansfield’s hiring and making friends with Dethe—occurred in the days before friended was a word, and long enough ago that there’s no obvious merit to revisiting the grade that Doug earned in Dr. Mansfield’s Physics 312: Mechanics. These days, it’s a remark by another of the candidates—a man whose name is lost to us now—that has reasserted itself in whatever part of the brain is responsible for commingling long-forgotten moments with recent experience.

public domain

SLAC Aerial View (US Geological Survey)

As a part of the interview process, the young particle physicist, who was doing a post-doc at SLAC (the Stanford Linear Accelerator), joined a small group of physics undergrads for lunch. During the meal, the physicist talked little of his work, but spent much time on the other things that interested him in life. Perhaps, he was trying to convince the assembled students, all males, that he was a fully realized human being and not one of those physics automatons that most undergrads fear greatly. At some point during the luncheon conversation, the physicist made one of those remarks that stays with you long after the name of the speaker is forgotten. He said, “When I was at CERN, I measured my bike rides in kilotons and megatons.”

What was meant to be a joke still falls flat. Presumably because of the absence of laughter, he went on to explain that continental towns and cities were geographically close enough that expressing distances in kilometers had been replaced by measurements mapped onto the nuclear kilotonnage and megatonnage of blast radii. (For blast maps, click here.) This remark was presented as common European vernacular at that time, but despite working with a variety of Europeans from the High Energy Physics community during the middle of the last decade (2004-2008) and while doing his own PhD (1999-2005), Doug has never heard another similar phrasing. Maybe, like many aspects of the Cold War, once it was over, that bit of verbiage, clearly expressing a European anxiety at being caught in the middle of a Russian-American game of nuclear lawn darts, was swept into history’s dustbin.

Castle Bravo, U.S. Biggest Nuclear Blast

Even though it wasn’t much of joke, the remark does serve as a reminder of the difficulty of capturing the destructive power of nuclear weapons in a way that is meaningful to humans. We recently watched Trinity and Beyond. This 1995 film, narrated by a post-T.J.-Hooker and pre-Denny-Crane William Shatner, contains a short section about the test of a Russian thermonuclear weapon known as Tsar Bomba. The explosive yield of Tsar Bomba—or Big Ivan—has been reported as 50 megatons or maybe 58 megatons, reduced from its originally planned 100 megatons. Whatever its actual yield—50, 58, or even 100 megatons—the number is effectively meaningless to most human brains.

One comparison that does resonate can be found in the Wikipedia entry for Tsar Bomba, which provides a calculation that equates the explosion to a split-second’s output (.39 nanoseconds to be exact) of our Sun. For that evanescent moment, the explosion of Tsar Bomba was 1.4% as energetic as the Sun. Again, the numbers may be relatively opaque, but the intent is clear: that weapon produced more than one percent of the energy of the Sun! The same powerful Sun responsible for all of our plants, heat, and weather—that Sun! And we actually exploded this on our own planet? Damn. If we’d exploded 100 (and yes, we’ve exploded way more than a hundred nuclear weapons) at once, blasts on the Earth’s surface would be 1.4 times more powerful than the Sun.

Comparisons like this are meant to express a measurement of the unthinkable. While we were at NASA’s Kennedy Space Center, we noticed a similar comparison, which came up in several venues—tour guides mentioned it, plaques proclaimed it. The sound of launching a Saturn V rocket was the second-loudest event on earth, second only to the detonation of an atomic bomb. One of the interesting special features on the Trinity and Beyond DVD was a real-time nuclear weapons test, in which silence surrounds the visual explosion until the shock wave finally reaches the microphone. Usually, such a film is edited, and if there’s sound, it’s synced up with the image, or, even more common, the sound is musical soundtrack designed to stir an emotional response, which is what the comparisons convey in relation to scale.

Released to Public Domain

US and USSR Nuclear Stockpiles (Fastfission)

The Cold War is over now. In 1966, when the Cold War was sizzling and with five nations in the world’s nuclear club, the United States supposedly had 32,000 nuclear weapons. In 1988, when we were in college and the Cold War was waning, the Soviet Union is said to have had 45,000 nuclear weapons. This year, according to the Bulletin of Atomic Scientists, there remain more than 22,000 nuclear weapons in the world, with almost 8000 of them ready to go.

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Comments»

1. Dethe Elza - December 8, 2010

Hey Doug and Anna.

When the Olympics were here in Vancouver last winter, signs went up all over town showing the walking distance to Olympic venues. For the life of me they always looked like bomb blast radii charts.

Nowadays I think the equivalent fear comes from rising sea levels: http://flood.firetree.net/?ll=49.2660,-123.1046&z=6

2. maggie - December 10, 2010

you might have been referring to the area of association in the brain where something stored in the brain is brought forward to the consciousness by it being related in some fact to a present thought .


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