1 00:00:01,800 --> 00:00:04,320 Speaker 1: Welcome to brain Stuff, a production of I Heart Radio, 2 00:00:06,600 --> 00:00:13,360 Speaker 1: Hey brain Stuff Lauren Bogbaum. Here. On August, about eleven 3 00:00:13,440 --> 00:00:17,160 Speaker 1: billion miles away from the Sun, the NASA probe Voyager 4 00:00:17,280 --> 00:00:21,479 Speaker 1: one left the heliosphere, boldly going where no man made 5 00:00:21,520 --> 00:00:25,759 Speaker 1: object had gone before. By crossing that boundary, Voyager one 6 00:00:25,840 --> 00:00:29,520 Speaker 1: traveled beyond the Solar System and entered interstellar space, a 7 00:00:29,720 --> 00:00:34,280 Speaker 1: historic first. If you look at the bottom row of 8 00:00:34,320 --> 00:00:37,640 Speaker 1: a traditional periodic table, you'll find the element that made 9 00:00:37,680 --> 00:00:43,760 Speaker 1: this cosmic adventure possible. Plutonium. First identified in the nineteen forties, 10 00:00:43,800 --> 00:00:47,840 Speaker 1: Plutonium has been used for both creative and destructive purposes. 11 00:00:48,520 --> 00:00:52,240 Speaker 1: The late physicist John Goffman once called plutonium the element 12 00:00:52,360 --> 00:00:56,639 Speaker 1: of the Lord of Hell. Every atom of plutonium contains 13 00:00:56,760 --> 00:01:00,400 Speaker 1: ninety four protons on the periodic table. This places it 14 00:01:00,440 --> 00:01:04,040 Speaker 1: after uranium with its ninety two protons, and neptunium with 15 00:01:04,200 --> 00:01:08,560 Speaker 1: ninety three. Uranium was first identified and named after the planet, 16 00:01:08,640 --> 00:01:11,600 Speaker 1: which was named after the ancient god Yuranus, back in 17 00:01:11,920 --> 00:01:16,840 Speaker 1: seventy nine. The researchers who identified neptunium in nineteen forty 18 00:01:16,920 --> 00:01:20,480 Speaker 1: followed suit, and later that year so did Glenn Seaborg 19 00:01:20,560 --> 00:01:25,000 Speaker 1: and his co workers at Berkeley Laboratory when they discovered plutonium. 20 00:01:25,200 --> 00:01:28,200 Speaker 1: Just ten years earlier, astronomers had observed a new dwarf 21 00:01:28,240 --> 00:01:31,800 Speaker 1: planet near Neptune to honor the Roman god of the underworld. 22 00:01:31,959 --> 00:01:35,759 Speaker 1: It was dubbed Pluto, and plutonium derives its name from 23 00:01:35,800 --> 00:01:41,080 Speaker 1: that heavenly body. Originally, Seaborgan Company were able to produce 24 00:01:41,160 --> 00:01:45,560 Speaker 1: plutonium by using a particle accelerator at Berkeley. With this device, 25 00:01:45,720 --> 00:01:49,640 Speaker 1: particles called deuterons were fired at a uranium sample. The 26 00:01:49,720 --> 00:01:53,680 Speaker 1: experiment created a small amount of neptunium, which then became 27 00:01:53,720 --> 00:02:00,000 Speaker 1: plutonium through a decaying process. But the first waveable plutoniums 28 00:02:00,000 --> 00:02:04,400 Speaker 1: sample was created at the University of Chicago on August two. 29 00:02:05,280 --> 00:02:11,680 Speaker 1: By that point, some parties had recognized the elements military potential. Okay, 30 00:02:11,840 --> 00:02:15,440 Speaker 1: let's talk about isotopes. So atoms of any given element 31 00:02:15,520 --> 00:02:18,560 Speaker 1: will always have the same number of protons in their nucleus, 32 00:02:18,760 --> 00:02:22,600 Speaker 1: but the number of neutrons can vary. These variations are 33 00:02:22,639 --> 00:02:27,000 Speaker 1: called isotopes of an element. After one of uranium's isotopes, 34 00:02:27,360 --> 00:02:30,680 Speaker 1: uranium two thirty five, was identified as a potential fuel 35 00:02:30,680 --> 00:02:36,359 Speaker 1: source for nuclear weapons, plutonium entered the conversation too. Plutonium 36 00:02:36,440 --> 00:02:39,360 Speaker 1: was the key ingredient in the first atomic bomb explosion 37 00:02:39,480 --> 00:02:43,880 Speaker 1: on Earth, which took place July sixty five. It was 38 00:02:43,880 --> 00:02:45,840 Speaker 1: in New Mexico, and it was strong enough to be 39 00:02:45,880 --> 00:02:48,000 Speaker 1: felt a hundred miles or more than a hundred and 40 00:02:48,040 --> 00:02:51,680 Speaker 1: fifty kilometers away. It was part of the Manhattan Project's 41 00:02:51,760 --> 00:02:56,240 Speaker 1: top secret Trinity nuclear test, and no uranium based weapons 42 00:02:56,280 --> 00:03:01,079 Speaker 1: were deployed for the experiment. However, uranium two thirty five 43 00:03:01,320 --> 00:03:03,480 Speaker 1: was the fuel in the weapon that the United States 44 00:03:03,600 --> 00:03:06,560 Speaker 1: used to destroy Hiroshima, Japan on August six of nine. 45 00:03:08,080 --> 00:03:10,799 Speaker 1: Plutonium was the fuel in the bomb that destroyed Nagasaki 46 00:03:10,840 --> 00:03:14,720 Speaker 1: three days later, killing tens of thousands of civilians fatally, 47 00:03:14,760 --> 00:03:18,480 Speaker 1: injuring many more, and effectively ending World War Two and 48 00:03:18,639 --> 00:03:23,639 Speaker 1: kicking off the Cold War. But beyond its use in weapons, 49 00:03:24,040 --> 00:03:28,079 Speaker 1: is plutonium dangerous. It is both chemically toxic and emits 50 00:03:28,120 --> 00:03:31,760 Speaker 1: ionizing radiation, but you'll likely never be exposed to it. 51 00:03:31,760 --> 00:03:34,720 Speaker 1: It only occurs in trace amounts in nature when certain 52 00:03:34,760 --> 00:03:38,600 Speaker 1: types of uranium decay. It could possibly be released into 53 00:03:38,600 --> 00:03:41,400 Speaker 1: the environment via an industrial plant, but there are many 54 00:03:41,400 --> 00:03:44,680 Speaker 1: safeguards against this. If you did encounter some, it could 55 00:03:44,720 --> 00:03:46,960 Speaker 1: burn your skin if you touched it, but the main 56 00:03:47,080 --> 00:03:49,640 Speaker 1: danger would be from inhaling small particles of it that 57 00:03:49,680 --> 00:03:52,120 Speaker 1: could get taken up by your system and transferred to 58 00:03:52,200 --> 00:03:55,320 Speaker 1: your liver and bones, where it might eventually cause cancer. 59 00:03:56,400 --> 00:03:58,880 Speaker 1: Even though it's a dangerous element, plutonium is far from 60 00:03:58,960 --> 00:04:02,000 Speaker 1: being the most toxic substance known to man, as activist 61 00:04:02,040 --> 00:04:06,320 Speaker 1: Ralph Nader once proclaimed, and today more than one third 62 00:04:06,360 --> 00:04:09,920 Speaker 1: of the energy produced at nuclear power plants comes from plutonium. 63 00:04:10,080 --> 00:04:13,120 Speaker 1: The United States, however, doesn't have any facilities that rely 64 00:04:13,240 --> 00:04:17,760 Speaker 1: on plutonium for energy. The most common plutonium isotope formed 65 00:04:17,760 --> 00:04:20,880 Speaker 1: in a nuclear reactor is plutonium two thirty nine, which 66 00:04:20,920 --> 00:04:24,440 Speaker 1: is created by neutron capture from depleted uranium two thirty eight. 67 00:04:25,120 --> 00:04:27,640 Speaker 1: When used for fission, plutonium two thirty nine can have 68 00:04:27,680 --> 00:04:30,599 Speaker 1: as much energy as enriched uranium two thirty five, which 69 00:04:30,680 --> 00:04:35,960 Speaker 1: is also used in nuclear weapons. Historically, another plutonium isotope, 70 00:04:36,000 --> 00:04:39,000 Speaker 1: plutonium two thirty eight, was used to power the batteries 71 00:04:39,040 --> 00:04:42,800 Speaker 1: in some commercial pacemakers. Those medical devices went out of 72 00:04:42,839 --> 00:04:47,560 Speaker 1: style as lithium powered alternatives hit the market, but in 73 00:04:47,600 --> 00:04:52,560 Speaker 1: the final frontier, plutonium remains a valuable commodity. For the 74 00:04:52,640 --> 00:04:54,960 Speaker 1: article this episode is based on, has to Work Spook 75 00:04:55,040 --> 00:04:57,479 Speaker 1: via email with Peter C. Burns, a chemist at the 76 00:04:57,520 --> 00:05:01,800 Speaker 1: University of Notre Dame. He said the most significant, lesser 77 00:05:01,839 --> 00:05:05,920 Speaker 1: known use of plutonium is for power generation during space exploration. 78 00:05:06,440 --> 00:05:08,960 Speaker 1: Plutonium two thirty eight emits a lot of heat when 79 00:05:08,960 --> 00:05:12,440 Speaker 1: it undergoes radioactive decay, and this heat can be used 80 00:05:12,440 --> 00:05:17,360 Speaker 1: in a thermoelectric generator to produce electricity. That's just one 81 00:05:17,440 --> 00:05:20,760 Speaker 1: quality that makes this isotope very attractive to engineers working 82 00:05:20,800 --> 00:05:24,159 Speaker 1: for space agencies. There's also its half life, which is 83 00:05:24,160 --> 00:05:26,000 Speaker 1: how long it takes for half of the atoms in 84 00:05:26,000 --> 00:05:29,279 Speaker 1: a given sample to decay and transform into something else. 85 00:05:30,040 --> 00:05:33,080 Speaker 1: With a respectable half life of eighty eight years, plutonium 86 00:05:33,120 --> 00:05:35,760 Speaker 1: two thirty eight can keep rovers and space probes running 87 00:05:35,760 --> 00:05:39,560 Speaker 1: for decades on end far away from the Sun in 88 00:05:39,640 --> 00:05:42,560 Speaker 1: places where the stars raise are weak and dim, the 89 00:05:42,600 --> 00:05:46,240 Speaker 1: solar powered satellites aren't going to perform that well, and 90 00:05:46,520 --> 00:05:49,800 Speaker 1: Mars rovers that depend on sunlight, like the now defunct 91 00:05:49,800 --> 00:05:52,720 Speaker 1: Opportunity Rover, have had to contend with the dust from 92 00:05:52,760 --> 00:05:56,760 Speaker 1: passing storms that can smother their panels and impede battery function. 93 00:05:58,000 --> 00:06:00,640 Speaker 1: For these reasons, plutonium two thirty eight is a great 94 00:06:00,640 --> 00:06:04,760 Speaker 1: fit for both Martian and deep space exploration. So far, 95 00:06:05,000 --> 00:06:07,839 Speaker 1: plutonium two thirty eight has powered at least thirty U 96 00:06:07,920 --> 00:06:11,479 Speaker 1: S space vehicles. The Perseverance Rover, the touchdown on the 97 00:06:11,480 --> 00:06:15,600 Speaker 1: Red Planet in February, has a generator fueled by plutonium 98 00:06:15,640 --> 00:06:19,000 Speaker 1: two thirty eight. This so do far flung spacecrafts like 99 00:06:19,200 --> 00:06:21,960 Speaker 1: Voyager one and Voyager two, which have been touring the 100 00:06:22,000 --> 00:06:31,280 Speaker 1: Solar System and beyond since nine Today's episode is based 101 00:06:31,320 --> 00:06:34,680 Speaker 1: on the article radioactive, a profile of the element plutonium 102 00:06:34,720 --> 00:06:37,000 Speaker 1: on how stuff works dot com, written by Mark Vancini. 103 00:06:37,480 --> 00:06:39,719 Speaker 1: Brain Stuff is production of Our Heart Radio in partnership 104 00:06:39,720 --> 00:06:41,520 Speaker 1: with how stuff works dot com, and it's produced by 105 00:06:41,520 --> 00:06:44,840 Speaker 1: Tyler Klang. Four more podcasts from my heart Radio visit 106 00:06:44,839 --> 00:06:47,520 Speaker 1: the heart Radio app, Apple Podcasts, or wherever you listen 107 00:06:47,600 --> 00:06:48,560 Speaker 1: to your favorite shows.