1 00:00:00,280 --> 00:00:05,200 Speaker 1: This Day in History Class is a production of iHeartRadio. 2 00:00:06,880 --> 00:00:10,680 Speaker 1: Hello and Welcome to This Day in History Class, a 3 00:00:10,760 --> 00:00:14,440 Speaker 1: show that discovers something new about history every day of 4 00:00:14,480 --> 00:00:18,560 Speaker 1: the week. I'm Gabe Lucier, and in this episode, we're 5 00:00:18,600 --> 00:00:22,640 Speaker 1: talking about the day when mankind first encountered helium, the 6 00:00:22,680 --> 00:00:25,880 Speaker 1: noble gas that adds lyft to our balloons, gives us 7 00:00:25,920 --> 00:00:30,640 Speaker 1: squeaky voices, and keeps the large Hadron collider from exploding. 8 00:00:38,159 --> 00:00:43,520 Speaker 1: The day was August eighteenth, eighteen sixty eight. French astronomer 9 00:00:43,560 --> 00:00:48,560 Speaker 1: Pierre Jules Cesar Janssen discovered an unknown element while observing 10 00:00:48,560 --> 00:00:52,080 Speaker 1: a solar eclipse. What he saw later turned out to 11 00:00:52,080 --> 00:00:56,840 Speaker 1: be helium, the first extraterrestrial element ever discovered, as it 12 00:00:56,880 --> 00:01:01,080 Speaker 1: had never been found before on Earth. The mid nineteenth 13 00:01:01,080 --> 00:01:04,280 Speaker 1: century was an exciting time for the field of astronomy. 14 00:01:04,720 --> 00:01:09,240 Speaker 1: In eighteen fifty nine, for example, German researchers Gustav Kirchoff 15 00:01:09,520 --> 00:01:12,280 Speaker 1: and Robert Bunsen worked out a way to determine the 16 00:01:12,319 --> 00:01:17,479 Speaker 1: composition of heavenly bodies. They discovered that heating different elements 17 00:01:17,520 --> 00:01:21,640 Speaker 1: produced bright lines of light which were visible through a spectroscope, 18 00:01:22,000 --> 00:01:25,880 Speaker 1: a kind of prism that disperses light into measurable wavelengths. 19 00:01:26,600 --> 00:01:30,240 Speaker 1: The scientists also learned that each element produces its own 20 00:01:30,360 --> 00:01:34,560 Speaker 1: unique spectrum, which meant that if they turned their spectroscopes skyward, 21 00:01:34,800 --> 00:01:37,880 Speaker 1: they'd be able to identify the elemental makeup of the 22 00:01:37,959 --> 00:01:41,520 Speaker 1: Sun and stars based on the lines of light they emitted. 23 00:01:42,520 --> 00:01:47,240 Speaker 1: After this breakthrough, Yanson and his fellow stargazers threw themselves 24 00:01:47,319 --> 00:01:51,680 Speaker 1: head first into this new form of light analysis. Although 25 00:01:51,680 --> 00:01:55,360 Speaker 1: he lived in Paris, Jansen traveled all over Europe and Asia, 26 00:01:55,640 --> 00:01:58,560 Speaker 1: hunting down the best positions from which to observe the 27 00:01:58,680 --> 00:02:03,040 Speaker 1: night sky. He also chased after solar eclipses, as those 28 00:02:03,080 --> 00:02:06,840 Speaker 1: events provided the rare chance to study the colorful, flamelike 29 00:02:07,000 --> 00:02:10,840 Speaker 1: bursts that emanated from the Sun, something we now know 30 00:02:11,000 --> 00:02:15,240 Speaker 1: to be hot clouds of dense gas called solar prominences. 31 00:02:16,160 --> 00:02:19,040 Speaker 1: At the time, scientists thought the spectrum of the Sun 32 00:02:19,200 --> 00:02:22,440 Speaker 1: could only be observed during an eclipse, So to make 33 00:02:22,480 --> 00:02:26,480 Speaker 1: the most of this seemingly rare opportunity, Jansen would travel 34 00:02:26,520 --> 00:02:30,040 Speaker 1: to a spot within the eclipse's narrow path of totality 35 00:02:30,320 --> 00:02:33,560 Speaker 1: so that he'd have the best vantage point possible. His 36 00:02:33,760 --> 00:02:37,440 Speaker 1: quest took him to Italy in February of eighteen sixty seven, 37 00:02:37,880 --> 00:02:40,680 Speaker 1: and then the following summer he traveled all the way 38 00:02:40,760 --> 00:02:45,400 Speaker 1: to Gunter, India to witness that year solar eclipse. Both 39 00:02:45,400 --> 00:02:48,560 Speaker 1: of those expeditions were funded by the French government and 40 00:02:48,600 --> 00:02:51,799 Speaker 1: its National Academy of Sciences, at a cost of more 41 00:02:51,840 --> 00:02:56,360 Speaker 1: than seventy thousand francs total. Thankfully, on the morning of 42 00:02:56,400 --> 00:03:01,000 Speaker 1: August eighteenth, eighteen sixty eight, the nations invested paid off. 43 00:03:01,680 --> 00:03:04,280 Speaker 1: Jansen watched as the Moon passed in front of the 44 00:03:04,320 --> 00:03:08,600 Speaker 1: Sun and revealed the solar prominences that were otherwise invisible 45 00:03:08,639 --> 00:03:12,360 Speaker 1: to the human eye. He noticed, as did many others 46 00:03:12,400 --> 00:03:15,720 Speaker 1: that day, that the glowing emissions were mostly composed of 47 00:03:15,800 --> 00:03:21,280 Speaker 1: super hot hydrogen gas. However, Jansen also spotted something that 48 00:03:21,400 --> 00:03:25,760 Speaker 1: most others overlooked. While looking through his spectroscope, he realized 49 00:03:25,800 --> 00:03:28,839 Speaker 1: there was a line of yellow light that didn't correspond 50 00:03:28,960 --> 00:03:32,880 Speaker 1: to the wavelength of any known element. It came closest 51 00:03:32,919 --> 00:03:35,760 Speaker 1: to that of sodium, but was different enough to warrant 52 00:03:35,840 --> 00:03:39,920 Speaker 1: further investigation. According to the science of his day, that 53 00:03:40,040 --> 00:03:43,360 Speaker 1: investigation would have to wait until the next solar eclipse, 54 00:03:43,800 --> 00:03:47,680 Speaker 1: but Yanson wasn't so sure. He thought that the mysterious 55 00:03:47,720 --> 00:03:50,640 Speaker 1: line might be bright enough to be viewed even without 56 00:03:50,640 --> 00:03:52,800 Speaker 1: the aid of an eclipse, so long as you had 57 00:03:52,800 --> 00:03:55,600 Speaker 1: a way to filter out all the other wavelengths of 58 00:03:55,680 --> 00:04:00,080 Speaker 1: visible light. Jansen's hypothesis would later bear fruit in the 59 00:04:00,120 --> 00:04:04,480 Speaker 1: form of the spectro helioscope, a special telescope dedicated to 60 00:04:04,600 --> 00:04:08,600 Speaker 1: examining the spectrum of the Sun. Jansen didn't know it, 61 00:04:08,760 --> 00:04:13,160 Speaker 1: but some five thousand miles away, English astronomer Joseph Norman 62 00:04:13,280 --> 00:04:17,560 Speaker 1: Lockyer had reached the same conclusion. In fact, the two 63 00:04:17,640 --> 00:04:21,560 Speaker 1: scientists each wrote a paper detailing their observations, and in 64 00:04:21,600 --> 00:04:24,480 Speaker 1: a strange twist, both of them arrived at the French 65 00:04:24,520 --> 00:04:29,360 Speaker 1: Academy of Sciences on the same day. The papers overlapped 66 00:04:29,400 --> 00:04:33,360 Speaker 1: on nearly every point, including descriptions of the mysterious yellow 67 00:04:33,440 --> 00:04:36,400 Speaker 1: light and of how to view the Sun without an eclipse. 68 00:04:37,080 --> 00:04:40,320 Speaker 1: The synchronicity of the two reports posed a problem for 69 00:04:40,400 --> 00:04:43,599 Speaker 1: the Academy, Namely, they didn't know who to credit for 70 00:04:43,640 --> 00:04:47,840 Speaker 1: the discovery, because although Yanson had made his observations first 71 00:04:48,120 --> 00:04:51,800 Speaker 1: on August eighteenth, both men's work was made public on 72 00:04:51,839 --> 00:04:56,360 Speaker 1: this same later date. Faced with an impossible choice, fellow 73 00:04:56,400 --> 00:05:01,159 Speaker 1: astronomer Herve Faye suggested a compromise. Instead of trying to 74 00:05:01,160 --> 00:05:04,880 Speaker 1: proportion the merit of the discovery and consequently diminishing it, 75 00:05:05,040 --> 00:05:08,720 Speaker 1: he said, would it be better to attribute impartially the 76 00:05:08,760 --> 00:05:12,080 Speaker 1: whole honor to both of these men of science, who 77 00:05:12,120 --> 00:05:15,799 Speaker 1: separated by some thousands of miles, have each been fortunate 78 00:05:15,920 --> 00:05:19,200 Speaker 1: enough to reach the intangible and invisible by a method 79 00:05:19,279 --> 00:05:22,440 Speaker 1: which is probably the most astonishing that the genius of 80 00:05:22,480 --> 00:05:27,960 Speaker 1: observation has ever conceived. Jansen and Lockyer thought that would 81 00:05:27,960 --> 00:05:30,800 Speaker 1: be better, and agreed to share credit for the discovery. 82 00:05:31,440 --> 00:05:35,000 Speaker 1: There was still a big lingering question, though, what exactly 83 00:05:35,200 --> 00:05:39,560 Speaker 1: had they discovered. The most straightforward explanation was that the 84 00:05:39,640 --> 00:05:43,960 Speaker 1: yellow light represented a new, unknown element, one that hadn't 85 00:05:44,000 --> 00:05:47,479 Speaker 1: yet been found on Earth. But at the time many 86 00:05:47,520 --> 00:05:50,559 Speaker 1: scientists found that hard to believe, and since they didn't 87 00:05:50,600 --> 00:05:54,240 Speaker 1: have spectro helioscopes of their own to see the evidence themselves, 88 00:05:54,600 --> 00:05:59,760 Speaker 1: they assumed it wasn't true. Lockyer ignored the naysayers, asserting 89 00:05:59,760 --> 00:06:02,599 Speaker 1: that he had indeed helped discover a new element and 90 00:06:02,640 --> 00:06:05,760 Speaker 1: that he believed it could also exist on Earth. He 91 00:06:05,839 --> 00:06:09,000 Speaker 1: even went so far as to name it, calling it helium, 92 00:06:09,279 --> 00:06:13,640 Speaker 1: after the Greek name for the sun helios. Some members 93 00:06:13,640 --> 00:06:17,480 Speaker 1: of the scientific community ridiculed Lockyer and Jansen for their 94 00:06:17,520 --> 00:06:21,720 Speaker 1: so called discovery. Others believed them, but thought that helium 95 00:06:21,800 --> 00:06:25,800 Speaker 1: could exist only in space. There were several efforts to 96 00:06:25,880 --> 00:06:29,039 Speaker 1: recreate the element in a lab, most notably those of 97 00:06:29,120 --> 00:06:34,880 Speaker 1: English chemist Edward Franklin, but every attempt ended in failure. Finally, though, 98 00:06:34,960 --> 00:06:38,600 Speaker 1: in eighteen eighty two, helium was discovered on Earth by 99 00:06:38,600 --> 00:06:44,760 Speaker 1: the Italian physicist Luigi Palmieri. While analyzing lava from Mount Vesuvius. 100 00:06:44,839 --> 00:06:47,719 Speaker 1: He heated up the gas inside a chunk of uranium 101 00:06:47,760 --> 00:06:53,320 Speaker 1: ore and observed the unmistakable yellow spectral line of helium. 102 00:06:53,600 --> 00:06:57,719 Speaker 1: Twelve years after that, the Scottish chemist William Ramsay further 103 00:06:57,800 --> 00:07:01,560 Speaker 1: experimented with the gas and found definitive proof that helium 104 00:07:01,600 --> 00:07:06,880 Speaker 1: occurs naturally on Earth. Jansen and lockyar were finally vindicated, 105 00:07:07,200 --> 00:07:11,960 Speaker 1: and mankind officially had a new element to play with. Today, 106 00:07:12,160 --> 00:07:15,040 Speaker 1: helium is best known as the gas that fills balloons 107 00:07:15,080 --> 00:07:17,960 Speaker 1: and makes your voice sound funny at parties, but it 108 00:07:18,000 --> 00:07:21,400 Speaker 1: actually has several important applications that have nothing to do 109 00:07:21,480 --> 00:07:25,040 Speaker 1: with your birthday. For example, helium is often used in 110 00:07:25,080 --> 00:07:28,760 Speaker 1: airbags as its non toxic, non flammable, and has a 111 00:07:28,840 --> 00:07:33,360 Speaker 1: high expansion rate. Another useful attribute of helium is that 112 00:07:33,440 --> 00:07:36,679 Speaker 1: its liquid state has the lowest boiling point of any 113 00:07:36,720 --> 00:07:40,440 Speaker 1: material on the planet. Not only does that make helium 114 00:07:40,480 --> 00:07:44,360 Speaker 1: invaluable to cryogenics, it also makes it uniquely suited as 115 00:07:44,400 --> 00:07:47,480 Speaker 1: a coolant for everything from the magnets in an MRI 116 00:07:47,760 --> 00:07:50,880 Speaker 1: scanner to the LCD screen on your phone or TV. 117 00:07:52,000 --> 00:07:55,040 Speaker 1: The only real downside to helium is that it isn't 118 00:07:55,160 --> 00:07:58,680 Speaker 1: very easy to access. Earth's supply of the gas is 119 00:07:58,760 --> 00:08:02,960 Speaker 1: generated deep undergrad through the natural radioactive decay of heavy 120 00:08:02,960 --> 00:08:07,480 Speaker 1: elements such as uranium and thorium. That means that even 121 00:08:07,480 --> 00:08:10,560 Speaker 1: though helium is the second most abundant element in the 122 00:08:10,600 --> 00:08:15,120 Speaker 1: known universe after hydrogen, it's still relatively rare on Earth. 123 00:08:15,920 --> 00:08:19,080 Speaker 1: So rare, in fact, that Pierre Jansen had to look 124 00:08:19,200 --> 00:08:24,320 Speaker 1: way out in space just to find it. I'm Gabe 125 00:08:24,400 --> 00:08:27,760 Speaker 1: Lucier and hopefully you now know a little more about 126 00:08:27,800 --> 00:08:31,840 Speaker 1: history today than you did yesterday. You can learn even 127 00:08:31,880 --> 00:08:35,120 Speaker 1: more about history by following us on Twitter, Facebook, and 128 00:08:35,160 --> 00:08:39,720 Speaker 1: Instagram at TDI HC Show, and if you have any 129 00:08:39,760 --> 00:08:42,560 Speaker 1: comments or suggestions you'd like to share, you can pass 130 00:08:42,600 --> 00:08:47,120 Speaker 1: them along by writing to this day at iHeartMedia dot com. 131 00:08:47,240 --> 00:08:49,960 Speaker 1: Thanks to Chandler Mays for producing the show, and thank 132 00:08:49,960 --> 00:08:52,640 Speaker 1: you for listening. I'll see you back here again soon 133 00:08:52,960 --> 00:09:09,520 Speaker 1: for another day in History class