1 00:00:00,120 --> 00:00:01,920 Speaker 1: This Day in History Class is a production of I 2 00:00:02,080 --> 00:00:07,840 Speaker 1: Heart Radio. Hello everyone, I'm Eves and you're listening to 3 00:00:07,880 --> 00:00:10,480 Speaker 1: This Day in History Class, a podcast that brings you 4 00:00:10,600 --> 00:00:14,000 Speaker 1: a different moment in history every single day. And before 5 00:00:14,040 --> 00:00:15,760 Speaker 1: we start the show, I just wanted to say that 6 00:00:15,840 --> 00:00:17,760 Speaker 1: I know a lot of us are having a really 7 00:00:17,760 --> 00:00:20,480 Speaker 1: hard time now and we're in really different situations than 8 00:00:20,520 --> 00:00:24,480 Speaker 1: we're used to. But I do hope that this podcast 9 00:00:24,520 --> 00:00:28,240 Speaker 1: provides you with some sort of enlightenment or a moment 10 00:00:28,240 --> 00:00:30,800 Speaker 1: in your day that can help you carry on, and 11 00:00:30,880 --> 00:00:34,839 Speaker 1: just operates as a reminder that time does go on. 12 00:00:36,400 --> 00:00:55,440 Speaker 1: Today is April. The day was April nine. Astronomer is 13 00:00:55,480 --> 00:00:59,560 Speaker 1: Harlow Shapley and HEYBERD. Curtis presented their opposing points about 14 00:00:59,560 --> 00:01:02,480 Speaker 1: the scale of the universe in an event sometimes called 15 00:01:02,600 --> 00:01:07,480 Speaker 1: the Great Debate. Hayber Curtis found his interest in astronomy 16 00:01:07,480 --> 00:01:10,400 Speaker 1: in the eighteen nineties. He studied at the University of 17 00:01:10,480 --> 00:01:14,000 Speaker 1: Virginia on a Vanderbilt fellowship and got his doctorate there. 18 00:01:14,040 --> 00:01:18,480 Speaker 1: In nineteen o two. Lick Observatory in California hired him, 19 00:01:18,560 --> 00:01:20,920 Speaker 1: and he stayed at Lake for the next eighteen years. 20 00:01:21,520 --> 00:01:24,240 Speaker 1: During his time there, nebula were one of the subjects 21 00:01:24,280 --> 00:01:27,640 Speaker 1: that he was invested in. At the time, the word 22 00:01:27,760 --> 00:01:31,560 Speaker 1: nebula referred to any celestial object that appeared fuzzy through 23 00:01:31,600 --> 00:01:35,160 Speaker 1: a telescope. Through his work, Curtis began to support the 24 00:01:35,200 --> 00:01:38,959 Speaker 1: island universe theory. He was convinced that certain nebulae were 25 00:01:39,040 --> 00:01:43,559 Speaker 1: island universes comparable to our own galaxy. In nineteen eighteen, 26 00:01:43,600 --> 00:01:45,840 Speaker 1: he published a study of seven hundred and sixty two 27 00:01:45,920 --> 00:01:49,120 Speaker 1: nebulae that he had photographed with the cross Ley reflector, 28 00:01:49,720 --> 00:01:53,400 Speaker 1: but many other astronomers were more skeptical of the theory. 29 00:01:54,480 --> 00:01:57,920 Speaker 1: Harlow Shapley got his doctorate in astronomy from Princeton University 30 00:01:58,000 --> 00:02:01,040 Speaker 1: in nineteen thirteen. The next year, he went to Mount 31 00:02:01,040 --> 00:02:05,360 Speaker 1: Wilson Observatory in California. There he studied the distribution of 32 00:02:05,400 --> 00:02:10,240 Speaker 1: globular clusters in the Milky Way. Through his observations, Shapily 33 00:02:10,280 --> 00:02:13,079 Speaker 1: determined that our solar system is not at the center 34 00:02:13,160 --> 00:02:16,359 Speaker 1: of the galaxy. At this point, it was widely believed 35 00:02:16,400 --> 00:02:19,079 Speaker 1: that the Sun was at the center of the galaxy, 36 00:02:19,120 --> 00:02:22,120 Speaker 1: but Shapily concluded that the Sun was around fifty thousand 37 00:02:22,160 --> 00:02:25,840 Speaker 1: light years away from the center. He also concluded that 38 00:02:25,880 --> 00:02:28,920 Speaker 1: the galaxy was around three hundred thousand light years in 39 00:02:28,960 --> 00:02:33,120 Speaker 1: diameter and thirty thousand light years thick. That meant that 40 00:02:33,200 --> 00:02:37,840 Speaker 1: the galaxy was much larger than previously thought. These numbers 41 00:02:37,880 --> 00:02:41,799 Speaker 1: were later revised, but his contributions provided a more realistic 42 00:02:41,919 --> 00:02:45,440 Speaker 1: estimate for the size of the galaxy. The nature of 43 00:02:45,440 --> 00:02:48,360 Speaker 1: spiral nebulee was also a subject of debate at the time. 44 00:02:48,960 --> 00:02:52,280 Speaker 1: Shapley believed that our galaxy is enormous and that spiral 45 00:02:52,320 --> 00:02:55,320 Speaker 1: nebulee were part of it, while Curtis did not buy 46 00:02:55,320 --> 00:02:59,480 Speaker 1: into Shapley's size for the Milky Way. However, Curtis maintained 47 00:02:59,480 --> 00:03:03,080 Speaker 1: his belief spiral nebula were other galaxies comparable to the 48 00:03:03,120 --> 00:03:08,240 Speaker 1: Milky Way. Astronomer Adrian von Mannen's research on spiral nebulae 49 00:03:08,280 --> 00:03:12,080 Speaker 1: at Mount Wilson gave Shapley even more fuel to doubt 50 00:03:12,120 --> 00:03:16,080 Speaker 1: the validity of the island universe theory. These differences and 51 00:03:16,120 --> 00:03:19,640 Speaker 1: thought led to the so called Great Debate of April nine. 52 00:03:20,880 --> 00:03:23,960 Speaker 1: Shapley and Curtis presented their positions at a meeting of 53 00:03:24,000 --> 00:03:28,840 Speaker 1: the National Academy of Sciences in Washington, d c. Shapley 54 00:03:28,919 --> 00:03:32,160 Speaker 1: argued his findings on the large dimensions of the galaxy, 55 00:03:32,240 --> 00:03:34,720 Speaker 1: saying that if the spiral nebula were as large as 56 00:03:34,760 --> 00:03:39,360 Speaker 1: our galaxy, they would have to be inconceivably large distances away. 57 00:03:39,560 --> 00:03:42,360 Speaker 1: He thought that the spiral nebulae were clusters made up 58 00:03:42,400 --> 00:03:46,600 Speaker 1: mostly of gas. Curtis, on the other hand, noted the 59 00:03:46,640 --> 00:03:50,200 Speaker 1: great distances to the spiral nebulae, arguing that all of 60 00:03:50,240 --> 00:03:53,720 Speaker 1: them could not be in our small Milky Way. No 61 00:03:53,800 --> 00:03:57,280 Speaker 1: clear winner emerged in the aftermath of the discussion, but 62 00:03:57,360 --> 00:03:59,840 Speaker 1: Shaply turned out to be right about the enormity of 63 00:03:59,840 --> 00:04:02,440 Speaker 1: the Oky Way and the Sun not being at its center, 64 00:04:03,080 --> 00:04:05,880 Speaker 1: and Curtis was right about the spiral nebula being outside 65 00:04:05,880 --> 00:04:11,560 Speaker 1: our galaxy. In astronomer Edwin Hubble announced that the spiral 66 00:04:11,640 --> 00:04:16,760 Speaker 1: nebula Andromeda was actually a galaxy. Modern estimates put the 67 00:04:16,839 --> 00:04:22,440 Speaker 1: number of galaxies in the universe at two trillion. I'm 68 00:04:22,440 --> 00:04:24,960 Speaker 1: Eves Jeff Cote and hopefully you know a little more 69 00:04:25,040 --> 00:04:28,920 Speaker 1: about history today than you did yesterday. And if you'd 70 00:04:28,920 --> 00:04:31,800 Speaker 1: like to send us any suggestions or comments, you can 71 00:04:31,839 --> 00:04:34,479 Speaker 1: hit us up on social media where at T d 72 00:04:34,600 --> 00:04:37,480 Speaker 1: I h C Podcast. You can also send us an 73 00:04:37,480 --> 00:04:41,039 Speaker 1: email at this day at i heeart media dot com. 74 00:04:41,040 --> 00:04:42,960 Speaker 1: Thanks again for listening to the show and we'll see 75 00:04:42,960 --> 00:04:53,160 Speaker 1: you tomorrow. For more podcasts from iHeart Radio, visit the 76 00:04:53,200 --> 00:04:55,800 Speaker 1: iHeart Radio app, Apple Podcasts, or where ever you listen 77 00:04:55,839 --> 00:04:56,680 Speaker 1: to your favorite shows.