1 00:00:00,040 --> 00:00:03,040 Speaker 1: Hey, everyone. Technically you're getting two days in history today 2 00:00:03,120 --> 00:00:05,920 Speaker 1: because we're running two episodes from the History Vault. I 3 00:00:06,000 --> 00:00:11,760 Speaker 1: hope you enjoy. Hey, guys, welcome to this Day in 4 00:00:11,840 --> 00:00:15,040 Speaker 1: History class, where we bring you a new tidbit from 5 00:00:15,080 --> 00:00:28,920 Speaker 1: history every day. The day was April nine. At the 6 00:00:29,000 --> 00:00:33,400 Speaker 1: Chernobyl Nuclear power Station and Soviet Ukraine, a chemical explosion 7 00:00:33,479 --> 00:00:38,960 Speaker 1: cost an enormous fire. Large quantities of radioactive material were 8 00:00:38,960 --> 00:00:42,400 Speaker 1: released into the atmosphere for nearly two weeks because of 9 00:00:42,400 --> 00:00:47,400 Speaker 1: the accident. Even though people in the nearby area were evacuated, 10 00:00:47,840 --> 00:00:52,080 Speaker 1: the wind spread the radiation, which contaminated land and caused 11 00:00:52,159 --> 00:00:57,120 Speaker 1: thousands of people to get radiation related illnesses. The Chernobyl 12 00:00:57,200 --> 00:01:00,200 Speaker 1: Power Station was in the town of Pripyat to us 13 00:01:00,240 --> 00:01:03,880 Speaker 1: northwest of the city of Chernobyl. The station was built 14 00:01:03,920 --> 00:01:07,640 Speaker 1: in the late nineteen seventies. It had four reactors, or 15 00:01:07,760 --> 00:01:11,800 Speaker 1: devices where nuclear fission is initiated and controlled in a 16 00:01:11,840 --> 00:01:17,280 Speaker 1: self sustaining chain reaction to create energy or radiation. Each 17 00:01:17,319 --> 00:01:21,399 Speaker 1: of the reactors could produce one thousand megawatts of electric power. 18 00:01:22,680 --> 00:01:27,360 Speaker 1: On the evening of April six, engineers began a test 19 00:01:27,400 --> 00:01:31,160 Speaker 1: on reactor Unit four. They wanted to figure out whether 20 00:01:31,200 --> 00:01:34,880 Speaker 1: the reactors turbine could run emergency water pumps during a 21 00:01:34,920 --> 00:01:39,160 Speaker 1: power loss, but the test and reactor were not designed will. 22 00:01:40,360 --> 00:01:43,880 Speaker 1: The engineers shut down the reactors, power regulating system and 23 00:01:43,920 --> 00:01:48,280 Speaker 1: emergency safety systems. Then they let the reactor run at 24 00:01:48,280 --> 00:01:51,400 Speaker 1: a low power and removed most of the control rods 25 00:01:51,440 --> 00:01:55,160 Speaker 1: from its core. Control rods maintained the fission rate in 26 00:01:55,200 --> 00:01:59,080 Speaker 1: a nuclear reactor. The reactor's output went up to two 27 00:01:59,160 --> 00:02:04,760 Speaker 1: hundred megawats, and at one am on April, the engineers 28 00:02:04,880 --> 00:02:07,760 Speaker 1: shut down the turbine engine to see if it's inertial 29 00:02:07,840 --> 00:02:12,280 Speaker 1: spinning would power the reactor's water pumps. It did not 30 00:02:13,240 --> 00:02:17,160 Speaker 1: because there was no cooling water. The reactor's power levels surged, 31 00:02:17,760 --> 00:02:20,480 Speaker 1: so the engineers put all the control rods back into 32 00:02:20,520 --> 00:02:24,560 Speaker 1: the reactor at once. That was supposed to prevent a meltdown. 33 00:02:25,200 --> 00:02:29,919 Speaker 1: The problem was the control rods had graphite tips. Those 34 00:02:29,960 --> 00:02:32,760 Speaker 1: graphite tips made the chain reaction in the court go 35 00:02:32,880 --> 00:02:36,000 Speaker 1: out of control and steam building up, and the reactor 36 00:02:36,120 --> 00:02:40,679 Speaker 1: blasted the steel and concrete lid off of it. Radioactive 37 00:02:40,720 --> 00:02:43,960 Speaker 1: debris went flying everywhere, and there was a partial meltdown 38 00:02:44,040 --> 00:02:48,040 Speaker 1: in the reactor core. Another explosion went off seconds later, 39 00:02:48,400 --> 00:02:52,239 Speaker 1: and the fire went off at reactor number three. Because 40 00:02:52,320 --> 00:02:56,600 Speaker 1: engineers had shut down emergency systems, safeties were not triggered, 41 00:02:56,760 --> 00:03:01,480 Speaker 1: though this was not a violation of regulations. The explosion 42 00:03:01,520 --> 00:03:05,240 Speaker 1: released four hundred times more radiation than the atomic bomb 43 00:03:05,320 --> 00:03:09,680 Speaker 1: the US dropped on Hiroshima. About thirty one people died 44 00:03:09,720 --> 00:03:12,480 Speaker 1: in the first few months after the explosion from the blast, 45 00:03:12,840 --> 00:03:19,160 Speaker 1: acute radiation, sickness, and cardiac arrest. Firefighters arrived minutes after 46 00:03:19,200 --> 00:03:22,440 Speaker 1: the fire started, but they were not wearing any gear 47 00:03:22,560 --> 00:03:25,320 Speaker 1: that would protect them from the radiation, and many of 48 00:03:25,360 --> 00:03:29,160 Speaker 1: them soon died from exposure. At five in the morning. 49 00:03:29,200 --> 00:03:32,720 Speaker 1: The next day, reactor three was shut down. The day 50 00:03:32,720 --> 00:03:36,520 Speaker 1: after that, reactors one and two were shut down. The 51 00:03:36,600 --> 00:03:39,880 Speaker 1: fire was put out with sand, lead and nitrogen, which 52 00:03:39,920 --> 00:03:43,800 Speaker 1: took about two weeks, But the accident had released extremely 53 00:03:43,920 --> 00:03:47,680 Speaker 1: dangerous levels of radioactive substances like I had died went 54 00:03:47,800 --> 00:03:52,840 Speaker 1: thirty one, plutonium and caesium one thirty seven. The plumes 55 00:03:52,880 --> 00:03:56,280 Speaker 1: of radioactive material released into the air were carried for 56 00:03:56,400 --> 00:04:03,120 Speaker 1: miles by currents of air lethal rain fail throughout Ukraine, Russia, Belarus, 57 00:04:03,320 --> 00:04:07,240 Speaker 1: Scandinavia and other parts of Europe. Many more people were 58 00:04:07,280 --> 00:04:12,000 Speaker 1: exposed to high doses of radiation. On the twenty seventh 59 00:04:12,040 --> 00:04:16,200 Speaker 1: of April, the Soviet government began evacuating crapyots tens of 60 00:04:16,240 --> 00:04:20,720 Speaker 1: thousands of residents. At the time, evacuates did not know 61 00:04:20,800 --> 00:04:24,680 Speaker 1: how serious the accident had been. At first, the Soviet 62 00:04:24,760 --> 00:04:27,840 Speaker 1: Union tried to keep the accident a secret, not announcing 63 00:04:27,880 --> 00:04:31,080 Speaker 1: the scale of the disaster. But a few days after 64 00:04:31,120 --> 00:04:35,359 Speaker 1: the explosion, Swedish officials realized that high radiation levels in 65 00:04:35,440 --> 00:04:38,279 Speaker 1: Europe were the result of a nuclear accident in the 66 00:04:38,320 --> 00:04:43,240 Speaker 1: Soviet Union. So in April, the Soviet Union announced that 67 00:04:43,279 --> 00:04:47,479 Speaker 1: there was an accident at Chernobyl. In May, hundreds of 68 00:04:47,520 --> 00:04:51,200 Speaker 1: thousands of people called liquidators were sent to Chernobyl to 69 00:04:51,279 --> 00:04:54,520 Speaker 1: help clean up. They worked in short shifts as they 70 00:04:54,560 --> 00:04:58,760 Speaker 1: did not have adequate protective gear. Over several months, a 71 00:04:58,880 --> 00:05:02,360 Speaker 1: huge steel and I meant sarcophagus was built to encase 72 00:05:02,480 --> 00:05:07,359 Speaker 1: reactor for and prevent the further spread of radiation. Still, 73 00:05:07,600 --> 00:05:12,080 Speaker 1: thousands of people remained in contaminated areas. People got sick 74 00:05:12,120 --> 00:05:15,880 Speaker 1: from the radiation, which increased the incidence of thyroid cancer. 75 00:05:17,040 --> 00:05:21,839 Speaker 1: Animals and forests were also affected. The Chernobyl power station 76 00:05:22,080 --> 00:05:26,400 Speaker 1: wasn't decommissioned until two thousand. In two thousand and sixteen, 77 00:05:26,760 --> 00:05:30,120 Speaker 1: a new confinement was placed over the old sarcophagus, which 78 00:05:30,160 --> 00:05:34,839 Speaker 1: had been deemed unsound. Today there is a Chernobyl exclusion 79 00:05:34,920 --> 00:05:38,480 Speaker 1: zone that's about one thousand square miles where people cannot 80 00:05:38,600 --> 00:05:42,760 Speaker 1: live in. Agriculture is not allowed, but there are animals 81 00:05:42,760 --> 00:05:46,080 Speaker 1: like wolves and bison living at the site. There are 82 00:05:46,120 --> 00:05:48,600 Speaker 1: plans for a solar power plant to be constructed at 83 00:05:48,600 --> 00:05:52,839 Speaker 1: the site, and people can visit the abandoned territory as tourists, 84 00:05:53,600 --> 00:05:56,960 Speaker 1: but the radio activity is still affecting people and likely 85 00:05:57,000 --> 00:06:00,960 Speaker 1: will for decades. For example, cows of miles away from 86 00:06:00,960 --> 00:06:03,960 Speaker 1: the site still produce milk with high levels of radiation. 87 00:06:05,240 --> 00:06:08,680 Speaker 1: The number of deaths caused by the radioactivity is controversial, 88 00:06:09,080 --> 00:06:11,920 Speaker 1: as the long term health effects of radiation are hard 89 00:06:11,960 --> 00:06:16,600 Speaker 1: to pinpoint and statistics can be unreliable. Many fears of 90 00:06:16,720 --> 00:06:21,480 Speaker 1: radiation induced health issues are unsubstantiated, but estimates of the 91 00:06:21,480 --> 00:06:24,960 Speaker 1: death toll have ranged from a few thousand to an 92 00:06:24,960 --> 00:06:31,000 Speaker 1: improbable million. I'm Eve jeffco and hopefully you know a 93 00:06:31,000 --> 00:06:34,920 Speaker 1: little more about history today than you did yesterday. If 94 00:06:34,920 --> 00:06:37,360 Speaker 1: there's something that I missed in an episode, you can 95 00:06:37,360 --> 00:06:40,839 Speaker 1: share it with everybody else on Twitter, Instagram or Facebook 96 00:06:41,040 --> 00:06:45,760 Speaker 1: at T d I h C podcast. We'll see you 97 00:06:45,880 --> 00:06:55,640 Speaker 1: here in the same place tomorrow. Hello everyone, I'm Eaves 98 00:06:55,839 --> 00:06:58,760 Speaker 1: and you're listening to this day history class of podcasts 99 00:06:58,760 --> 00:07:02,000 Speaker 1: that brings you a different moment in history every single day. 100 00:07:02,480 --> 00:07:04,279 Speaker 1: And before we start the show, I just wanted to 101 00:07:04,320 --> 00:07:06,159 Speaker 1: say that I know a lot of us are having 102 00:07:06,200 --> 00:07:08,560 Speaker 1: a really hard time now and we're in really different 103 00:07:08,600 --> 00:07:12,440 Speaker 1: situations than we're used to. But I do hope that 104 00:07:12,520 --> 00:07:16,640 Speaker 1: this podcast provides you with some sort of enlightenment or 105 00:07:16,640 --> 00:07:18,760 Speaker 1: a moment in your day that can help you carry 106 00:07:18,840 --> 00:07:23,240 Speaker 1: on and just operates as a reminder that time does 107 00:07:23,400 --> 00:07:40,800 Speaker 1: go on. The day was April nineteen. Astronomer Is Harlow 108 00:07:40,840 --> 00:07:44,720 Speaker 1: Shapley and Hayber Curtis presented their opposing points about the 109 00:07:44,720 --> 00:07:47,720 Speaker 1: scale of the universe in an event sometimes called the 110 00:07:47,800 --> 00:07:52,600 Speaker 1: Great Debate. Hayber Curtis found his interest in astronomy in 111 00:07:52,640 --> 00:07:56,000 Speaker 1: the eighteen nineties. He studied at the University of Virginia 112 00:07:56,080 --> 00:07:59,160 Speaker 1: on a Vanderbilt fellowship and got his doctorate there In 113 00:07:59,240 --> 00:08:03,680 Speaker 1: nineteen o two. Lick Observatory in California hired him and 114 00:08:03,760 --> 00:08:06,840 Speaker 1: He stayed at Lake for the next eighteen years. During 115 00:08:06,880 --> 00:08:09,480 Speaker 1: his time there, nebula were one of the subjects that 116 00:08:09,560 --> 00:08:13,240 Speaker 1: he was invested in. At the time, the word nebula 117 00:08:13,400 --> 00:08:17,360 Speaker 1: referred to any celestial object that appeared fuzzy through a telescope. 118 00:08:18,240 --> 00:08:21,560 Speaker 1: Through his work, Curtis began to support the island universe theory. 119 00:08:22,080 --> 00:08:25,800 Speaker 1: He was convinced that certain nebulae were island universes comparable 120 00:08:25,840 --> 00:08:29,240 Speaker 1: to our own galaxy. In nineteen eighteen, he published a 121 00:08:29,280 --> 00:08:32,000 Speaker 1: study of seven hundred and sixty two nebulae that he 122 00:08:32,040 --> 00:08:36,200 Speaker 1: had photographed with the Crossley reflector, but many other astronomers 123 00:08:36,240 --> 00:08:40,720 Speaker 1: were more skeptical of the theory. Harlow Shapley got his 124 00:08:40,760 --> 00:08:44,680 Speaker 1: doctorate in astronomy from Princeton University in nineteen thirteen. The 125 00:08:44,720 --> 00:08:48,480 Speaker 1: next year, he went to Mount Wilson Observatory in California. 126 00:08:48,600 --> 00:08:51,760 Speaker 1: There he studied the distribution of globular clusters in the 127 00:08:51,800 --> 00:08:56,480 Speaker 1: Milky Way. Through his observations, Shapily determined that our solar 128 00:08:56,520 --> 00:08:59,760 Speaker 1: system is not at the center of the galaxy. At 129 00:08:59,760 --> 00:09:02,280 Speaker 1: this point, it was widely believed that the Sun was 130 00:09:02,360 --> 00:09:05,319 Speaker 1: at the center of the galaxy, but Shapily concluded that 131 00:09:05,360 --> 00:09:08,160 Speaker 1: the Sun was around fifty thousand light years away from 132 00:09:08,200 --> 00:09:12,240 Speaker 1: the center. He also concluded that the galaxy was around 133 00:09:12,320 --> 00:09:16,160 Speaker 1: three hundred thousand light years in diameter and thirty thousand 134 00:09:16,240 --> 00:09:19,520 Speaker 1: light years thick. That meant that the galaxy was much 135 00:09:19,720 --> 00:09:24,320 Speaker 1: larger than previously thought. These numbers were later revised, but 136 00:09:24,400 --> 00:09:27,960 Speaker 1: his contributions provided a more realistic estimate for the size 137 00:09:27,960 --> 00:09:31,760 Speaker 1: of the galaxy. The nature of spiral nebulee was also 138 00:09:31,840 --> 00:09:35,000 Speaker 1: a subject of debate at the time. Shapley believed that 139 00:09:35,000 --> 00:09:38,320 Speaker 1: our galaxy is enormous and that spiral nebulea were part 140 00:09:38,360 --> 00:09:41,680 Speaker 1: of it, while Curtis did not buy into Shapley's size 141 00:09:41,679 --> 00:09:45,080 Speaker 1: for the Milky Way. However, Curtis maintained his belief that 142 00:09:45,120 --> 00:09:49,200 Speaker 1: spiral nebule were other galaxies comparable to the Milky Way. 143 00:09:49,760 --> 00:09:53,760 Speaker 1: Astronomer Adrian von Maanen's research on spiral nebulee at Mount 144 00:09:53,760 --> 00:09:57,800 Speaker 1: Wilson gave Shapley even more fuel to doubt the validity 145 00:09:57,880 --> 00:10:01,720 Speaker 1: of the island universe theory. These differences and thought led 146 00:10:01,720 --> 00:10:05,800 Speaker 1: to the so called Great Debate of April nineteen twenty. 147 00:10:05,920 --> 00:10:09,000 Speaker 1: Shapley and Curtis presented their positions at a meeting of 148 00:10:09,040 --> 00:10:13,880 Speaker 1: the National Academy of Sciences in Washington. D. C. Shapley 149 00:10:13,960 --> 00:10:17,199 Speaker 1: argued his findings on the large dimensions of the galaxy, 150 00:10:17,320 --> 00:10:19,800 Speaker 1: saying that if the spiral nebulae were as large as 151 00:10:19,800 --> 00:10:24,400 Speaker 1: our galaxy, they would have to be inconceivably large distances away. 152 00:10:24,600 --> 00:10:27,360 Speaker 1: He thought that the spiral nebulae were clusters made up 153 00:10:27,440 --> 00:10:31,640 Speaker 1: mostly of gas. Curtis, on the other hand, noted the 154 00:10:31,720 --> 00:10:35,240 Speaker 1: great distances to the spiral nebulee, arguing that all of 155 00:10:35,280 --> 00:10:38,760 Speaker 1: them could not be in our small Milky Way. No 156 00:10:38,880 --> 00:10:42,320 Speaker 1: clear winner emerged in the aftermath of the discussion, but 157 00:10:42,440 --> 00:10:44,880 Speaker 1: Shapily turned out to be right about the enormity of 158 00:10:44,880 --> 00:10:47,480 Speaker 1: the Milky Way and the Sun not being at its center, 159 00:10:48,120 --> 00:10:50,920 Speaker 1: and Curtis was right about the spiral nebulee being outside 160 00:10:50,920 --> 00:10:56,080 Speaker 1: our galaxy. In ninety four, astronomer Edwin Hubbell announced that 161 00:10:56,120 --> 00:11:01,480 Speaker 1: the spiral nebula Andromeda was actually a galaxy. Modern estimates 162 00:11:01,559 --> 00:11:05,040 Speaker 1: put the number of galaxies in the universe at two trillion. 163 00:11:07,280 --> 00:11:09,840 Speaker 1: I'm Eve Jeff Cote, and hopefully you know a little 164 00:11:09,880 --> 00:11:13,760 Speaker 1: more about history today than you did yesterday, And if 165 00:11:13,800 --> 00:11:16,679 Speaker 1: you'd like to send us any suggestions or comments, you 166 00:11:16,720 --> 00:11:18,959 Speaker 1: can hit us up on social media where at t 167 00:11:19,320 --> 00:11:22,400 Speaker 1: d i h C Podcast. You can also send us 168 00:11:22,400 --> 00:11:26,080 Speaker 1: an email at this Day at i heeart media dot com. 169 00:11:26,080 --> 00:11:28,000 Speaker 1: Thanks again for listening to the show and we'll see 170 00:11:28,000 --> 00:11:38,160 Speaker 1: you tomorrow. For more podcasts from I Heart Radio, visit 171 00:11:38,200 --> 00:11:40,840 Speaker 1: the iHeart Radio app, Apple Podcasts, or wherever you listen 172 00:11:40,880 --> 00:11:41,760 Speaker 1: to your favorite shows.