1 00:00:01,840 --> 00:00:07,560 Speaker 1: Welcome to Brainstuff, a production of iHeartRadio, Hey brain Stuff, 2 00:00:07,600 --> 00:00:12,040 Speaker 1: Lauren Vogelbaum. Here You're sitting in a movie theater watching 3 00:00:12,080 --> 00:00:15,480 Speaker 1: the latest sci fi action film. The screen is filled 4 00:00:15,480 --> 00:00:18,960 Speaker 1: with an intense space battle. The theater booms with other 5 00:00:19,040 --> 00:00:23,120 Speaker 1: worldly noises. Is ship engines roar and wine, A laser's 6 00:00:23,200 --> 00:00:26,680 Speaker 1: hum in your seat rumbles? Is? Spacecraft explode left and right? 7 00:00:27,600 --> 00:00:29,720 Speaker 1: But if you were really able to watch the battle 8 00:00:29,760 --> 00:00:32,800 Speaker 1: in person, would you be able to hear anything at all? 9 00:00:34,200 --> 00:00:36,240 Speaker 1: If we look to science fiction films for the answer, 10 00:00:36,360 --> 00:00:39,839 Speaker 1: we get conflicting results. The tagline for the film Alien 11 00:00:40,080 --> 00:00:42,599 Speaker 1: was in space, no one can hear you scream, but 12 00:00:42,680 --> 00:00:46,839 Speaker 1: the film actually depicts noisy spaceships. A few examples, like 13 00:00:46,880 --> 00:00:48,760 Speaker 1: the film two thousand and one, A Space Odyssey and 14 00:00:48,800 --> 00:00:52,840 Speaker 1: the TV series Firefly have silent space scenes, but it's 15 00:00:52,880 --> 00:00:55,680 Speaker 1: more common in space fiction, like most of Star Wars 16 00:00:55,680 --> 00:00:58,800 Speaker 1: and Star Trek, to have dozens of scenes that combine 17 00:00:58,840 --> 00:01:02,840 Speaker 1: action and outer space with nifty sound effects. So which 18 00:01:02,880 --> 00:01:05,840 Speaker 1: fictional universe should we believe? Would you be unable to 19 00:01:05,840 --> 00:01:08,600 Speaker 1: hear the Enterprise if zipped right past you? Would the 20 00:01:08,640 --> 00:01:12,880 Speaker 1: destruction of the Death Star be completely silent? To get 21 00:01:12,880 --> 00:01:14,720 Speaker 1: to the bottom of this question, we need to look 22 00:01:14,760 --> 00:01:18,720 Speaker 1: at two important factors, how sound travels and what's actually 23 00:01:18,720 --> 00:01:23,440 Speaker 1: out there in space. A sound travels in mechanical waves. 24 00:01:23,840 --> 00:01:27,080 Speaker 1: A mechanical wave is a disturbance that moves and transports 25 00:01:27,200 --> 00:01:31,520 Speaker 1: energy from one place to another through a medium. In sound, 26 00:01:31,720 --> 00:01:35,240 Speaker 1: the disturbance is a vibration, and the medium can be 27 00:01:35,480 --> 00:01:39,600 Speaker 1: any series of interconnected and interactive particles. That means that 28 00:01:39,720 --> 00:01:44,600 Speaker 1: sound can travel through gases, liquids, and solids. For example, 29 00:01:44,720 --> 00:01:48,760 Speaker 1: imagine a church bell. When a bell rings, it vibrates, 30 00:01:48,880 --> 00:01:52,840 Speaker 1: a meaning the bell itself flexes inward and outward very rapidly. 31 00:01:53,560 --> 00:01:56,600 Speaker 1: As the bell moves outward, it pushes against the bits 32 00:01:56,600 --> 00:02:00,320 Speaker 1: of air immediately surrounding it. As we've talked about on 33 00:02:00,360 --> 00:02:03,680 Speaker 1: the show, air might seem like nothing to us, but 34 00:02:03,760 --> 00:02:06,800 Speaker 1: it's actually a sort of soup of particles and molecules. 35 00:02:07,640 --> 00:02:11,000 Speaker 1: So those air bits touching the bell then push against 36 00:02:11,040 --> 00:02:14,640 Speaker 1: other adjacent air bits and so on. Then, as the 37 00:02:14,639 --> 00:02:18,040 Speaker 1: bell flexes inward, it pulls against the adjacent air particles, 38 00:02:18,240 --> 00:02:21,919 Speaker 1: and they in turn pull against other air particles. This 39 00:02:22,040 --> 00:02:25,840 Speaker 1: push and pull pattern is a sound wave. The vibrating 40 00:02:25,840 --> 00:02:28,600 Speaker 1: bell is the original disturbance, and the air particles are 41 00:02:28,600 --> 00:02:33,320 Speaker 1: the medium through which the vibration travels. But sound isn't 42 00:02:33,360 --> 00:02:36,520 Speaker 1: restricted to moving through the air. Let's say you press 43 00:02:36,520 --> 00:02:39,040 Speaker 1: your ear against a solid surface like a table and 44 00:02:39,080 --> 00:02:42,000 Speaker 1: close your eyes. Then someone taps their finger at the 45 00:02:42,000 --> 00:02:45,840 Speaker 1: other end of the table. The tapping becomes the initial disturbance. 46 00:02:46,440 --> 00:02:49,639 Speaker 1: Each tap sends vibrations through the table, and the particles 47 00:02:49,639 --> 00:02:51,560 Speaker 1: in the table collide with each other and become the 48 00:02:51,600 --> 00:02:55,080 Speaker 1: medium for the sound wave. The particles and table collide 49 00:02:55,080 --> 00:02:57,120 Speaker 1: with the rim of your ear, so you might feel 50 00:02:57,120 --> 00:02:59,440 Speaker 1: the vibration in your ear or the rest of your head, 51 00:03:00,040 --> 00:03:02,920 Speaker 1: But they'll also collide with air particles trapped between the 52 00:03:02,960 --> 00:03:06,840 Speaker 1: table and your ear drum inside your ear. The ear 53 00:03:06,919 --> 00:03:10,560 Speaker 1: drum is also known as your ear's tympanic membrane. When 54 00:03:10,600 --> 00:03:13,120 Speaker 1: air particles hit it, this sets off a series of 55 00:03:13,200 --> 00:03:16,959 Speaker 1: vibrations in several structures inside the ear. The brain interprets 56 00:03:17,000 --> 00:03:21,520 Speaker 1: these vibrations as sounds. Basically, how hearing works is a 57 00:03:21,560 --> 00:03:27,200 Speaker 1: different episode. Okay, so sound needs a physical medium in 58 00:03:27,320 --> 00:03:31,000 Speaker 1: order to travel anywhere. Is there enough physical material in 59 00:03:31,120 --> 00:03:35,120 Speaker 1: space to act as a medium for sound waves. Before 60 00:03:35,160 --> 00:03:37,480 Speaker 1: we begin to talk about space, we should probably define 61 00:03:37,520 --> 00:03:39,440 Speaker 1: it because there's a lot of it out there and 62 00:03:39,520 --> 00:03:42,640 Speaker 1: it's not uniform. For the purposes of this discussion, will 63 00:03:42,680 --> 00:03:45,440 Speaker 1: consider space to be the region of the universe outside 64 00:03:45,440 --> 00:03:50,440 Speaker 1: of Earth's atmosphere. You've probably heard that space is a vacuum. 65 00:03:51,000 --> 00:03:54,120 Speaker 1: A true vacuum refers to the complete absence of matter, 66 00:03:54,720 --> 00:03:59,600 Speaker 1: but space contains stars, planets, asteroids, moons, comets, dust, which 67 00:03:59,640 --> 00:04:02,600 Speaker 1: is all a lot of matter. But space is still 68 00:04:02,600 --> 00:04:06,440 Speaker 1: considered a vacuum, or technically a near vacuum because space 69 00:04:06,760 --> 00:04:09,960 Speaker 1: is big of planets can be millions of miles apart, 70 00:04:10,040 --> 00:04:12,760 Speaker 1: and solar systems can have billions of miles between them. 71 00:04:13,440 --> 00:04:17,719 Speaker 1: This empty space, sometimes called interstellar space, is practically devoid 72 00:04:17,800 --> 00:04:22,080 Speaker 1: of all matter, and again, sound waves can only travel 73 00:04:22,200 --> 00:04:26,000 Speaker 1: through matter. In interstellar space, the distance between particles is 74 00:04:26,040 --> 00:04:28,200 Speaker 1: so great that they would never collide with each other. 75 00:04:28,760 --> 00:04:30,240 Speaker 1: Even if you could get a front seat for the 76 00:04:30,279 --> 00:04:33,440 Speaker 1: explosion of the dust star, you wouldn't hear anything at all. 77 00:04:35,480 --> 00:04:38,560 Speaker 1: That being said, there are a few arguments one could make. 78 00:04:39,839 --> 00:04:43,200 Speaker 1: Radio waves can travel through space. So if you're wearing 79 00:04:43,240 --> 00:04:45,520 Speaker 1: a space suit that contains a radio unit and one 80 00:04:45,560 --> 00:04:47,680 Speaker 1: of your buddies sends you a radio message there is 81 00:04:47,720 --> 00:04:50,000 Speaker 1: fresh pizza in the space station. You'd be able to 82 00:04:50,000 --> 00:04:55,000 Speaker 1: hear it. That's because radio waves aren't mechanical, they're electromagnetic. 83 00:04:55,480 --> 00:04:59,640 Speaker 1: Electromagnetic waves can transmit energy through a vacuum. Once your 84 00:04:59,720 --> 00:05:02,240 Speaker 1: radio receives a signal, it can convert it into sound, 85 00:05:02,400 --> 00:05:04,800 Speaker 1: which will travel through the air in your spacesuit without 86 00:05:04,839 --> 00:05:09,719 Speaker 1: a problem. Or let's say that you're drifting through space 87 00:05:09,760 --> 00:05:12,760 Speaker 1: while wearing a spacesuit and you accidentally bump your helmet 88 00:05:12,800 --> 00:05:16,279 Speaker 1: into the Hubble space telescope. The collision would make a 89 00:05:16,279 --> 00:05:18,600 Speaker 1: sound that you could hear even though you're in space. 90 00:05:19,240 --> 00:05:21,920 Speaker 1: That's because the sound waves would have a physical medium 91 00:05:21,960 --> 00:05:25,240 Speaker 1: to move through your helmet and the air inside your spacesuit. 92 00:05:25,720 --> 00:05:28,279 Speaker 1: You'd still be surrounded by a vacuum, so an independent 93 00:05:28,279 --> 00:05:30,960 Speaker 1: observer wouldn't be able to hear anything, no matter how 94 00:05:30,960 --> 00:05:34,880 Speaker 1: many times you had but a satellite. Or imagine you're 95 00:05:34,880 --> 00:05:37,320 Speaker 1: an astronaut on a mission at the International Space Station. 96 00:05:38,040 --> 00:05:40,280 Speaker 1: You've decided to step out into space, but forgot to 97 00:05:40,279 --> 00:05:43,599 Speaker 1: put on your spacesuit first. You press your ear against 98 00:05:43,640 --> 00:05:46,520 Speaker 1: the station, you won't have any air in your ear, 99 00:05:46,600 --> 00:05:50,000 Speaker 1: so you couldn't hear In the traditional sense. However, you 100 00:05:50,040 --> 00:05:53,080 Speaker 1: make out a few sounds through bone conduction, in which 101 00:05:53,120 --> 00:05:55,280 Speaker 1: sound waves travel through the bones of the jaw and 102 00:05:55,360 --> 00:05:58,920 Speaker 1: skull to the inner ear bypassing the ear drum. There's 103 00:05:58,960 --> 00:06:01,280 Speaker 1: no need for air, so you could hear your fellow 104 00:06:01,320 --> 00:06:05,320 Speaker 1: astronauts partying inside the shuttle for about fifteen seconds. After that, 105 00:06:05,360 --> 00:06:08,520 Speaker 1: you'd likely be unconscious and on your way to dead. 106 00:06:10,080 --> 00:06:14,600 Speaker 1: So yes, despite the wisdom of Hollywood filmmakers, it's impossible 107 00:06:14,640 --> 00:06:18,120 Speaker 1: to hear noises in space. We suggest the next time 108 00:06:18,120 --> 00:06:20,160 Speaker 1: that you watch a science fiction film you plug your 109 00:06:20,200 --> 00:06:22,680 Speaker 1: ears up whenever anything happens within the vacuum of space. 110 00:06:22,960 --> 00:06:25,560 Speaker 1: It'll make the film seem more realistic and probably work 111 00:06:25,640 --> 00:06:27,839 Speaker 1: as a great conversational topic with your friends once the 112 00:06:27,880 --> 00:06:35,080 Speaker 1: movie's over. Today's episode is based on the article can 113 00:06:35,200 --> 00:06:37,719 Speaker 1: humans here in Space? On how stuffworks dot com written 114 00:06:37,720 --> 00:06:41,360 Speaker 1: by Jonathan Strickland. Brainstuff is production of iHeartRadio in partnership 115 00:06:41,360 --> 00:06:43,800 Speaker 1: with how stuffworks dot Com, and it's produced by Tyler Klang. 116 00:06:44,320 --> 00:06:47,280 Speaker 1: Four more podcasts my heart Radio, visit the iHeartRadio app, 117 00:06:47,400 --> 00:07:00,839 Speaker 1: Apple Podcasts, or wherever you listen to your favorite shows.