At least 340,000 Americans died from radioactive fallout between 1951 and 1973

Domestic nuclear testing wreaked havoc on thousands of families.

At least 340,000 Americans died from radioactive fallout between 1951 and 1973
Wikimedia Commons
  • Hiroshima and Nagasaki resulted in the deaths of hundreds of thousands. But new research shows that domestic U.S. nuclear tests likely killed more.
  • The new research tracked an unlikely vector for radioactive transmission: dairy cows.
  • The study serves as a reminder of the insidious and deadly nature of nuclear weapons.

When we think of nuclear disasters, a few names probably come to mind. There's the Chernobyl disaster, which killed around 27,000 people, although estimates are fuzzy. After Fukushima, there were no deaths due to radiation poisoning, but this event occurred relatively recently, and radiation poisoning often kills slowly over decades. When the U.S. dropped atomic bombs on Hiroshima and Nagasaki, estimates put the death toll at around 200,000 people, but again, exact numbers are difficult to calculate.

One name that almost certainly didn't come to mind is Nevada. When the Soviet Union detonated their first atomic bomb in 1949, the U.S. was shocked into action. America's prior nuclear testing had been carried out in the Pacific, but it was logistically slow and costly to conduct tests there. In order to maintain dominance over the growing Soviet threat, the U.S. selected a 1,375 square-mile area in Nye County, Nevada.

This was an ideal spot for several reasons. It was closer than Bikini Atoll. The weather was predictable and very dry, reducing the risk that radioactive fallout would be dispersed by rainstorms. It was sparsely populated. There was an understanding that there would be some amount of risk posed to nearby civilians, but it was deemed acceptable at the time. The trouble is, our understanding of radioactive fallout was still in its infancy. It was a catch-22; the only way to learn more was to test nuclear weapons.

New research with a wider scope

Subsidence craters at the Nevada test site. These craters result from underground weapons testing, typically from nuclear weapons. Federal Government of the United States [Public domain], via Wikimedia Commons

In the 1950s, the U.S. government downplayed the danger of radioactive fallout, asserting that all radioactivity was confined to the Nevada test site. Despite this, a national estimate attributed 49,000 cancer deaths to nuclear testing in the area.

But the results of new research suggest that this number is woefully inaccurate. Using a novel method, and today's improved understanding of radioactive fallout, Keith Meyers from the University of Arizona discovered that U.S. nuclear testing was responsible for the deaths of at least as many — and likely more — as those killed by the nuclear bombs in Hiroshima and Nagasaki. Specifically, between 340,000 and 690,000 Americans died from radioactive fallout from 1951 to 1973.

Prior studies generally looked at the areas surrounded the Nevada test site and estimated the deaths caused by fallout from the area. This number was relatively low, owing to the dry, predictable weather mentioned earlier. However, the bulk of the deaths were actually dispersed throughout the country, primarily in the Midwest and Northeast regions. These deaths were caused by an unfortunate synergy between meteorology, radiation, and — perhaps oddly enough — cows.

An unforeseen vector of radiation poisoning

Through an unforeseen chain of events, dairy cows became a vector for radioactive poisoning. ROBYN BECK/AFP/Getty Image

Out of all the radioactive elements produced by a nuclear explosion, iodine-131 was the biggest killer. I-131 has an eight-day half-life, tends to accumulate in the thyroid gland, and emits beta and gamma radiation. While alpha radiation is generally weak and doesn't penetrate material very well, beta and gamma radiation are highly energetic and shoot through clothing and flesh, ripping up DNA as it goes along.

Prior studies had examined the radioactive fallout dispersed by low-altitude winds, which would generally settle around the Nevada test site. However, a significant amount of I-131 was caught up in high-altitude winds. These winds carried the radioactive particles to other regions of the U.S., where it mixed with rain clouds.

The now-radioactive rain fell onto the grasslands in the Midwest and Northeast. Then, cows ate the now-radioactive grass. The cows then produced radioactive milk. Dairy practices during the study period were different than they are today — most people drank milk that had recently been extracted from local cows.

Thanks to a National Cancer Institute database that contains broad data on radiation exposure, Meyers was able to track the amount of I-131 found in local milk and compare this with the number and nature of deaths on a county level. In this way, Meyers was able to determine that a significant number of these deaths were due to drinking poisoned milk. These civilians would have had no idea that the milk they were drinking had been irradiated by nuclear explosions hundreds of miles away.

Ironically, the area around the Nevada test site didn't have this problem. Although they too drank fresh milk from local cows, they imported hay from other parts of the country. Since their cows weren't eating irradiated hay, the local Nevadans took in significantly less radioactive material than their less-fortunate, distant countrymen.

Although our understanding of radiation and nuclear fallout is much improved since the dawn of the nuclear age, the study serves as a warning of the insidious nature of nuclear weapons. Containing nuclear fallout is challenging, even when you know where all of the vectors of radioactive transmission are. The complexity and intertwining nature of our ecological and social systems means that words like "clean," "precise," or "surgical" will likely never apply to nuclear weapons.

This is what aliens would 'hear' if they flew by Earth

A Mercury-bound spacecraft's noisy flyby of our home planet.

Image source: sdecoret on Shutterstock/ESA/Big Think
Surprising Science
  • There is no sound in space, but if there was, this is what it might sound like passing by Earth.
  • A spacecraft bound for Mercury recorded data while swinging around our planet, and that data was converted into sound.
  • Yes, in space no one can hear you scream, but this is still some chill stuff.

First off, let's be clear what we mean by "hear" here. (Here, here!)

Sound, as we know it, requires air. What our ears capture is actually oscillating waves of fluctuating air pressure. Cilia, fibers in our ears, respond to these fluctuations by firing off corresponding clusters of tones at different pitches to our brains. This is what we perceive as sound.

All of which is to say, sound requires air, and space is notoriously void of that. So, in terms of human-perceivable sound, it's silent out there. Nonetheless, there can be cyclical events in space — such as oscillating values in streams of captured data — that can be mapped to pitches, and thus made audible.


Image source: European Space Agency

The European Space Agency's BepiColombo spacecraft took off from Kourou, French Guyana on October 20, 2019, on its way to Mercury. To reduce its speed for the proper trajectory to Mercury, BepiColombo executed a "gravity-assist flyby," slinging itself around the Earth before leaving home. Over the course of its 34-minute flyby, its two data recorders captured five data sets that Italy's National Institute for Astrophysics (INAF) enhanced and converted into sound waves.

Into and out of Earth's shadow

In April, BepiColombo began its closest approach to Earth, ranging from 256,393 kilometers (159,315 miles) to 129,488 kilometers (80,460 miles) away. The audio above starts as BepiColombo begins to sneak into the Earth's shadow facing away from the sun.

The data was captured by BepiColombo's Italian Spring Accelerometer (ISA) instrument. Says Carmelo Magnafico of the ISA team, "When the spacecraft enters the shadow and the force of the Sun disappears, we can hear a slight vibration. The solar panels, previously flexed by the Sun, then find a new balance. Upon exiting the shadow, we can hear the effect again."

In addition to making for some cool sounds, the phenomenon allowed the ISA team to confirm just how sensitive their instrument is. "This is an extraordinary situation," says Carmelo. "Since we started the cruise, we have only been in direct sunshine, so we did not have the possibility to check effectively whether our instrument is measuring the variations of the force of the sunlight."

When the craft arrives at Mercury, the ISA will be tasked with studying the planets gravity.

Magentosphere melody

The second clip is derived from data captured by BepiColombo's MPO-MAG magnetometer, AKA MERMAG, as the craft traveled through Earth's magnetosphere, the area surrounding the planet that's determined by the its magnetic field.

BepiColombo eventually entered the hellish mangentosheath, the region battered by cosmic plasma from the sun before the craft passed into the relatively peaceful magentopause that marks the transition between the magnetosphere and Earth's own magnetic field.

MERMAG will map Mercury's magnetosphere, as well as the magnetic state of the planet's interior. As a secondary objective, it will assess the interaction of the solar wind, Mercury's magnetic field, and the planet, analyzing the dynamics of the magnetosphere and its interaction with Mercury.

Recording session over, BepiColombo is now slipping through space silently with its arrival at Mercury planned for 2025.

Photo by Martin Adams on Unsplash
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