1 00:00:01,840 --> 00:00:08,600 Speaker 1: Welcome to Brainstuff, a production of iHeartRadio, Hey Brainstuff Lauren Vobebaum. Here. 2 00:00:10,240 --> 00:00:14,120 Speaker 1: Back in the sixteen hundreds, astronomer Galileo Galilei peered into 3 00:00:14,120 --> 00:00:18,279 Speaker 1: his telescope and discovered dark spots on the Sun. He 4 00:00:18,400 --> 00:00:22,599 Speaker 1: subsequently noticed that they seemed to move, vanishing and then returning. 5 00:00:24,040 --> 00:00:27,920 Speaker 1: He wrote in sixteen thirteen, it is also manifest that 6 00:00:27,960 --> 00:00:32,880 Speaker 1: their rotation is about the Sun, and though he noted 7 00:00:32,920 --> 00:00:35,360 Speaker 1: it was possible that the sun spots were moving while 8 00:00:35,400 --> 00:00:38,600 Speaker 1: the Sun stayed in place, he continued to me, it 9 00:00:38,640 --> 00:00:41,360 Speaker 1: seems more probable that the movement is of the solar 10 00:00:41,400 --> 00:00:47,360 Speaker 1: globe than of its surroundings. Galileo had discovered that the Sun, 11 00:00:47,960 --> 00:00:52,760 Speaker 1: like numerous other celestial objects, rotates on an axis, but 12 00:00:52,880 --> 00:00:55,240 Speaker 1: the length of time and manner in which the Sun 13 00:00:55,320 --> 00:00:58,000 Speaker 1: rotates is different than that of a rocky planet such 14 00:00:58,000 --> 00:01:03,600 Speaker 1: as Earth. That second difference actually causes the Sun spots 15 00:01:03,640 --> 00:01:08,679 Speaker 1: that originally led to Galileo's discovery. For the article, this 16 00:01:08,720 --> 00:01:12,000 Speaker 1: episode is based on How Stuff Works. Spoke with Clear Raptory, 17 00:01:12,200 --> 00:01:15,560 Speaker 1: a head of Education and Outreach for the National Solar Observatory, 18 00:01:15,880 --> 00:01:20,040 Speaker 1: the US Center for Ground Based Solar Physics. She said 19 00:01:20,440 --> 00:01:24,360 Speaker 1: pretty much, everything in the universe rotates, everything is moving 20 00:01:24,520 --> 00:01:31,119 Speaker 1: relative to everything else. That is a direct explanation that's 21 00:01:31,280 --> 00:01:35,960 Speaker 1: accurate and also opened a lot of questions for me. Okay, 22 00:01:36,640 --> 00:01:40,920 Speaker 1: researchers think that everything in the universe is moving and 23 00:01:41,120 --> 00:01:45,160 Speaker 1: rotating because they're all exerting gravity on each other. You know, 24 00:01:45,319 --> 00:01:48,880 Speaker 1: everything's pulling on everything else a little. And because the 25 00:01:48,960 --> 00:01:53,000 Speaker 1: universe was born with some amount of angular momentum or 26 00:01:53,200 --> 00:01:57,720 Speaker 1: rotational movement or spin, and angular momentum is a physical 27 00:01:57,760 --> 00:02:03,600 Speaker 1: property that is conserved. Let's unpack that a little. You've 28 00:02:03,640 --> 00:02:06,960 Speaker 1: probably encountered Newton's laws of motion, the first of which 29 00:02:07,000 --> 00:02:09,960 Speaker 1: is that an object in linear motion will stay in 30 00:02:10,040 --> 00:02:14,160 Speaker 1: motion unless something MUCKs around with it, and the same 31 00:02:14,160 --> 00:02:18,360 Speaker 1: basic rule applies to angular momentum. Left to its own devices, 32 00:02:18,400 --> 00:02:22,360 Speaker 1: an object that's spinning is going to keep spinning. These 33 00:02:22,480 --> 00:02:29,480 Speaker 1: rules are the conservation of momentum. So basically, the Sun 34 00:02:29,560 --> 00:02:32,880 Speaker 1: rotates on its axis now because everything in the galaxy 35 00:02:32,919 --> 00:02:37,079 Speaker 1: is rotating around the galaxy center. That includes the clouds 36 00:02:37,120 --> 00:02:39,920 Speaker 1: of dust and hydrogen gas that the Sun condensed from 37 00:02:40,080 --> 00:02:44,560 Speaker 1: billions of years ago. Those clouds were also whirling vaguely 38 00:02:44,639 --> 00:02:48,680 Speaker 1: around day shifting central point. But as the proto Sun 39 00:02:48,800 --> 00:02:52,799 Speaker 1: gradually gathered mass and developed the gravity that attracted more 40 00:02:52,880 --> 00:02:56,720 Speaker 1: and more nearby molecules to it, it also conserved that 41 00:02:56,840 --> 00:03:02,120 Speaker 1: angular momentum or spin, and in the same way that 42 00:03:02,160 --> 00:03:05,720 Speaker 1: a figure skater can spin faster by tucking their arms 43 00:03:05,760 --> 00:03:08,880 Speaker 1: in towards their body, the Sun went from a lazy 44 00:03:09,000 --> 00:03:12,760 Speaker 1: whirl to a relatively quick spin as it gathered mass. 45 00:03:15,680 --> 00:03:19,440 Speaker 1: The Sun's general rotation isn't difficult to measure because the 46 00:03:19,600 --> 00:03:24,160 Speaker 1: thin visible solar surface called the photosphere has visible features 47 00:03:24,280 --> 00:03:27,560 Speaker 1: like sun spots and prominences, some of which last long 48 00:03:27,639 --> 00:03:29,760 Speaker 1: enough that they can be observed as they move around, 49 00:03:30,040 --> 00:03:34,160 Speaker 1: just as Galileo did. But from there it gets a 50 00:03:34,200 --> 00:03:37,560 Speaker 1: little complicated. Remember that the Sun is made up of 51 00:03:37,640 --> 00:03:43,680 Speaker 1: plasma that is a super hot, electrically charged gas rafter 52 00:03:43,800 --> 00:03:47,080 Speaker 1: he said, It's not a solid body, so it doesn't 53 00:03:47,160 --> 00:03:51,240 Speaker 1: rotate as a single solid ball. Instead, the gas rotates 54 00:03:51,240 --> 00:03:56,280 Speaker 1: more rapidly at the equator than at the poles. A 55 00:03:56,280 --> 00:03:59,040 Speaker 1: spot at the equator goes around in just about twenty 56 00:03:59,080 --> 00:04:02,720 Speaker 1: four Earth day, while the polar regions take six whole 57 00:04:02,800 --> 00:04:06,720 Speaker 1: days longer or more. This is more similar to how 58 00:04:06,800 --> 00:04:09,400 Speaker 1: Jupiter and the other gas giant planets rotate than the 59 00:04:09,400 --> 00:04:14,840 Speaker 1: way that Earth or Mars rotates, and this differential rotation 60 00:04:15,200 --> 00:04:19,000 Speaker 1: is actually what causes sunspots and some other strange and 61 00:04:19,080 --> 00:04:23,520 Speaker 1: interesting features of the Sun. The Sun's magnetic field, which 62 00:04:23,520 --> 00:04:27,400 Speaker 1: is generated just below the surface, basically gets wrapped around 63 00:04:27,440 --> 00:04:32,080 Speaker 1: itself by this uneven motion. The result is development of 64 00:04:32,200 --> 00:04:36,360 Speaker 1: high density magnetic bands that eventually burst through the surface, 65 00:04:36,640 --> 00:04:39,880 Speaker 1: causing the eruptions that we see as sunspots and flares. 66 00:04:40,880 --> 00:04:43,680 Speaker 1: They appear in a regular eleven year cycle called the 67 00:04:43,720 --> 00:04:47,520 Speaker 1: solar cycle, during which the number of sunspots increases and 68 00:04:47,600 --> 00:04:54,119 Speaker 1: then decreases again. Beneath the photosphere lies the convection zone, 69 00:04:54,480 --> 00:04:59,000 Speaker 1: a thick layer where currents of plasma form. It rotates 70 00:04:59,200 --> 00:05:03,279 Speaker 1: roughly the same is the surface, but deeper inside the Sun. 71 00:05:03,600 --> 00:05:07,520 Speaker 1: Scientists aren't sure whether other parts, like the radiative zone 72 00:05:07,520 --> 00:05:11,760 Speaker 1: and the core, move at different rates. A Raftery said, 73 00:05:12,080 --> 00:05:14,680 Speaker 1: we have some good ideas about this, but it's still 74 00:05:14,720 --> 00:05:20,799 Speaker 1: an active question. Because scientists can't look into the Sun 75 00:05:20,920 --> 00:05:25,560 Speaker 1: beneath the photosphere, they instead study how it sounds. A 76 00:05:25,640 --> 00:05:29,560 Speaker 1: Raftery explained, the inside of the Sun acts almost like 77 00:05:29,600 --> 00:05:34,919 Speaker 1: a bell. There are sound waves bouncing around inside. To 78 00:05:34,960 --> 00:05:38,320 Speaker 1: measure these sound waves, the National Solar Observatory uses data 79 00:05:38,360 --> 00:05:42,599 Speaker 1: collected by its Global Oscillation Network Group or GONG, which 80 00:05:42,640 --> 00:05:45,039 Speaker 1: is an array of telescopes and other instruments at six 81 00:05:45,080 --> 00:05:49,159 Speaker 1: different locations around the world, and uses sophisticated mathematics to 82 00:05:49,240 --> 00:05:57,560 Speaker 1: discern solar vibrations. So will the Sun keep spinning forever? Yep? 83 00:05:57,960 --> 00:06:04,040 Speaker 1: Basically due to the aforemanvation of angular momentum. About five 84 00:06:04,080 --> 00:06:06,360 Speaker 1: billion years from now, the Sun will begin to run 85 00:06:06,400 --> 00:06:09,000 Speaker 1: out of fuel and expand into a red dwarf star, 86 00:06:09,600 --> 00:06:13,560 Speaker 1: then will collapse into a compact white dwarf and eventually 87 00:06:13,800 --> 00:06:18,000 Speaker 1: a dense stellar crystal. But even then it will continue 88 00:06:18,040 --> 00:06:22,880 Speaker 1: to rotate, though at different speeds, because pretty much everything 89 00:06:22,960 --> 00:06:31,920 Speaker 1: is rotating and always has been. Today's episode is based 90 00:06:31,960 --> 00:06:34,600 Speaker 1: on the article does the Sun Rotate? On how Stuffworks 91 00:06:34,600 --> 00:06:37,599 Speaker 1: dot Com? Written by Patrick J. Higer. Brain Stuff is 92 00:06:37,600 --> 00:06:40,440 Speaker 1: production by Heart Radio in partnership with how Stuffworks dot Com, 93 00:06:40,480 --> 00:06:43,359 Speaker 1: and it is produced by Tyler Klang. Four more podcasts 94 00:06:43,440 --> 00:06:46,960 Speaker 1: my heart Radio, visit the Aheartradio app, Apple Podcasts, or 95 00:06:46,960 --> 00:06:48,799 Speaker 1: wherever you listen to your favorite shows.