Welcome to brain Stuff, a production of I Heart Radio, Hey brain Stuff Lauren Bogbaum. Here. On August, about eleven billion miles away from the Sun, the NASA probe Voyager one left the heliosphere, boldly going where no man made object had gone before. By crossing that boundary, Voyager one traveled beyond the Solar System and entered interstellar space, a historic first. If you look at the bottom row of a traditional periodic table, you'll find the element that made
this cosmic adventure possible. Plutonium. First identified in the nineteen forties, Plutonium has been used for both creative and destructive purposes. The late physicist John Goffman once called plutonium the element of the Lord of Hell. Every atom of plutonium contains ninety four protons on the periodic table. This places it after uranium with its ninety two protons, and neptunium with
ninety three. Uranium was first identified and named after the planet, which was named after the ancient god Yuranus, back in seventy nine. The researchers who identified neptunium in nineteen forty followed suit, and later that year so did Glenn Seaborg and his co workers at Berkeley Laboratory when they discovered plutonium. Just ten years earlier, astronomers had observed a new dwarf planet near Neptune to honor the Roman god of the underworld.
It was dubbed Pluto, and plutonium derives its name from that heavenly body. Originally, Seaborgan Company were able to produce plutonium by using a particle accelerator at Berkeley. With this device, particles called deuterons were fired at a uranium sample. The experiment created a small amount of neptunium, which then became plutonium through a decaying process. But the first waveable plutoniums sample was created at the University of Chicago on August two.
By that point, some parties had recognized the elements military potential. Okay, let's talk about isotopes. So atoms of any given element will always have the same number of protons in their nucleus, but the number of neutrons can vary. These variations are called isotopes of an element. After one of uranium's isotopes, uranium two thirty five, was identified as a potential fuel
source for nuclear weapons, plutonium entered the conversation too. Plutonium was the key ingredient in the first atomic bomb explosion on Earth, which took place July sixty five. It was in New Mexico, and it was strong enough to be felt a hundred miles or more than a hundred and fifty kilometers away. It was part of the Manhattan Project's top secret Trinity nuclear test, and no uranium based weapons
were deployed for the experiment. However, uranium two thirty five was the fuel in the weapon that the United States used to destroy Hiroshima, Japan on August six of nine. Plutonium was the fuel in the bomb that destroyed Nagasaki three days later, killing tens of thousands of civilians fatally, injuring many more, and effectively ending World War Two and kicking off the Cold War. But beyond its use in weapons,
is plutonium dangerous. It is both chemically toxic and emits ionizing radiation, but you'll likely never be exposed to it. It only occurs in trace amounts in nature when certain types of uranium decay. It could possibly be released into the environment via an industrial plant, but there are many
safeguards against this. If you did encounter some, it could burn your skin if you touched it, but the main danger would be from inhaling small particles of it that could get taken up by your system and transferred to your liver and bones, where it might eventually cause cancer.
Even though it's a dangerous element, plutonium is far from being the most toxic substance known to man, as activist Ralph Nader once proclaimed, and today more than one third of the energy produced at nuclear power plants comes from plutonium. The United States, however, doesn't have any facilities that rely
on plutonium for energy. The most common plutonium isotope formed in a nuclear reactor is plutonium two thirty nine, which is created by neutron capture from depleted uranium two thirty eight. When used for fission, plutonium two thirty nine can have as much energy as enriched uranium two thirty five, which is also used in nuclear weapons. Historically, another plutonium isotope, plutonium two thirty eight, was used to power the batteries
in some commercial pacemakers. Those medical devices went out of style as lithium powered alternatives hit the market, but in the final frontier, plutonium remains a valuable commodity. For the article this episode is based on, has to Work Spook via email with Peter C. Burns, a chemist at the University of Notre Dame. He said the most significant, lesser known use of plutonium is for power generation during space exploration.
Plutonium two thirty eight emits a lot of heat when it undergoes radioactive decay, and this heat can be used in a thermoelectric generator to produce electricity. That's just one quality that makes this isotope very attractive to engineers working for space agencies. There's also its half life, which is how long it takes for half of the atoms in a given sample to decay and transform into something else.
With a respectable half life of eighty eight years, plutonium two thirty eight can keep rovers and space probes running for decades on end far away from the Sun in places where the stars raise are weak and dim, the solar powered satellites aren't going to perform that well, and Mars rovers that depend on sunlight, like the now defunct Opportunity Rover, have had to contend with the dust from passing storms that can smother their panels and impede battery function.
For these reasons, plutonium two thirty eight is a great fit for both Martian and deep space exploration. So far, plutonium two thirty eight has powered at least thirty U S space vehicles. The Perseverance Rover, the touchdown on the Red Planet in February, has a generator fueled by plutonium
two thirty eight. This so do far flung spacecrafts like Voyager one and Voyager two, which have been touring the Solar System and beyond since nine Today's episode is based on the article radioactive, a profile of the element plutonium on how stuff works dot com, written by Mark Vancini. Brain Stuff is production of Our Heart Radio in partnership with how stuff works dot com, and it's produced by
Tyler Klang. Four more podcasts from my heart Radio visit the heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.