Speaker 1: Welcome to Brainstuff, a production of iHeartRadio, Hey brain Stuff,
Speaker 1: Lauren Vogelbaum. Here You're sitting in a movie theater watching
Speaker 1: the latest sci fi action film. The screen is filled
Speaker 1: with an intense space battle. The theater booms with other
Speaker 1: worldly noises. Is ship engines roar and wine, A laser's
Speaker 1: hum in your seat rumbles? Is? Spacecraft explode left and right?
Speaker 1: But if you were really able to watch the battle
Speaker 1: in person, would you be able to hear anything at all?
Speaker 1: If we look to science fiction films for the answer,
Speaker 1: we get conflicting results. The tagline for the film Alien
Speaker 1: was in space, no one can hear you scream, but
Speaker 1: the film actually depicts noisy spaceships. A few examples, like
Speaker 1: the film two thousand and one, A Space Odyssey and
Speaker 1: the TV series Firefly have silent space scenes, but it's
Speaker 1: more common in space fiction, like most of Star Wars
Speaker 1: and Star Trek, to have dozens of scenes that combine
Speaker 1: action and outer space with nifty sound effects. So which
Speaker 1: fictional universe should we believe? Would you be unable to
Speaker 1: hear the Enterprise if zipped right past you? Would the
Speaker 1: destruction of the Death Star be completely silent? To get
Speaker 1: to the bottom of this question, we need to look
Speaker 1: at two important factors, how sound travels and what's actually
Speaker 1: out there in space. A sound travels in mechanical waves.
Speaker 1: A mechanical wave is a disturbance that moves and transports
Speaker 1: energy from one place to another through a medium. In sound,
Speaker 1: the disturbance is a vibration, and the medium can be
Speaker 1: any series of interconnected and interactive particles. That means that
Speaker 1: sound can travel through gases, liquids, and solids. For example,
Speaker 1: imagine a church bell. When a bell rings, it vibrates,
Speaker 1: a meaning the bell itself flexes inward and outward very rapidly.
Speaker 1: As the bell moves outward, it pushes against the bits
Speaker 1: of air immediately surrounding it. As we've talked about on
Speaker 1: the show, air might seem like nothing to us, but
Speaker 1: it's actually a sort of soup of particles and molecules.
Speaker 1: So those air bits touching the bell then push against
Speaker 1: other adjacent air bits and so on. Then, as the
Speaker 1: bell flexes inward, it pulls against the adjacent air particles,
Speaker 1: and they in turn pull against other air particles. This
Speaker 1: push and pull pattern is a sound wave. The vibrating
Speaker 1: bell is the original disturbance, and the air particles are
Speaker 1: the medium through which the vibration travels. But sound isn't
Speaker 1: restricted to moving through the air. Let's say you press
Speaker 1: your ear against a solid surface like a table and
Speaker 1: close your eyes. Then someone taps their finger at the
Speaker 1: other end of the table. The tapping becomes the initial disturbance.
Speaker 1: Each tap sends vibrations through the table, and the particles
Speaker 1: in the table collide with each other and become the
Speaker 1: medium for the sound wave. The particles and table collide
Speaker 1: with the rim of your ear, so you might feel
Speaker 1: the vibration in your ear or the rest of your head,
Speaker 1: But they'll also collide with air particles trapped between the
Speaker 1: table and your ear drum inside your ear. The ear
Speaker 1: drum is also known as your ear's tympanic membrane. When
Speaker 1: air particles hit it, this sets off a series of
Speaker 1: vibrations in several structures inside the ear. The brain interprets
Speaker 1: these vibrations as sounds. Basically, how hearing works is a
Speaker 1: different episode. Okay, so sound needs a physical medium in
Speaker 1: order to travel anywhere. Is there enough physical material in
Speaker 1: space to act as a medium for sound waves. Before
Speaker 1: we begin to talk about space, we should probably define
Speaker 1: it because there's a lot of it out there and
Speaker 1: it's not uniform. For the purposes of this discussion, will
Speaker 1: consider space to be the region of the universe outside
Speaker 1: of Earth's atmosphere. You've probably heard that space is a vacuum.
Speaker 1: A true vacuum refers to the complete absence of matter,
Speaker 1: but space contains stars, planets, asteroids, moons, comets, dust, which
Speaker 1: is all a lot of matter. But space is still
Speaker 1: considered a vacuum, or technically a near vacuum because space
Speaker 1: is big of planets can be millions of miles apart,
Speaker 1: and solar systems can have billions of miles between them.
Speaker 1: This empty space, sometimes called interstellar space, is practically devoid
Speaker 1: of all matter, and again, sound waves can only travel
Speaker 1: through matter. In interstellar space, the distance between particles is
Speaker 1: so great that they would never collide with each other.
Speaker 1: Even if you could get a front seat for the
Speaker 1: explosion of the dust star, you wouldn't hear anything at all.
Speaker 1: That being said, there are a few arguments one could make.
Speaker 1: Radio waves can travel through space. So if you're wearing
Speaker 1: a space suit that contains a radio unit and one
Speaker 1: of your buddies sends you a radio message there is
Speaker 1: fresh pizza in the space station. You'd be able to
Speaker 1: hear it. That's because radio waves aren't mechanical, they're electromagnetic.
Speaker 1: Electromagnetic waves can transmit energy through a vacuum. Once your
Speaker 1: radio receives a signal, it can convert it into sound,
Speaker 1: which will travel through the air in your spacesuit without
Speaker 1: a problem. Or let's say that you're drifting through space
Speaker 1: while wearing a spacesuit and you accidentally bump your helmet
Speaker 1: into the Hubble space telescope. The collision would make a
Speaker 1: sound that you could hear even though you're in space.
Speaker 1: That's because the sound waves would have a physical medium
Speaker 1: to move through your helmet and the air inside your spacesuit.
Speaker 1: You'd still be surrounded by a vacuum, so an independent
Speaker 1: observer wouldn't be able to hear anything, no matter how
Speaker 1: many times you had but a satellite. Or imagine you're
Speaker 1: an astronaut on a mission at the International Space Station.
Speaker 1: You've decided to step out into space, but forgot to
Speaker 1: put on your spacesuit first. You press your ear against
Speaker 1: the station, you won't have any air in your ear,
Speaker 1: so you couldn't hear In the traditional sense. However, you
Speaker 1: make out a few sounds through bone conduction, in which
Speaker 1: sound waves travel through the bones of the jaw and
Speaker 1: skull to the inner ear bypassing the ear drum. There's
Speaker 1: no need for air, so you could hear your fellow
Speaker 1: astronauts partying inside the shuttle for about fifteen seconds. After that,
Speaker 1: you'd likely be unconscious and on your way to dead.
Speaker 1: So yes, despite the wisdom of Hollywood filmmakers, it's impossible
Speaker 1: to hear noises in space. We suggest the next time
Speaker 1: that you watch a science fiction film you plug your
Speaker 1: ears up whenever anything happens within the vacuum of space.
Speaker 1: It'll make the film seem more realistic and probably work
Speaker 1: as a great conversational topic with your friends once the
Speaker 1: movie's over. Today's episode is based on the article can
Speaker 1: humans here in Space? On how stuffworks dot com written
Speaker 1: by Jonathan Strickland. Brainstuff is production of iHeartRadio in partnership
Speaker 1: with how stuffworks dot Com, and it's produced by Tyler Klang.
Speaker 1: Four more podcasts my heart Radio, visit the iHeartRadio app,
Speaker 1: Apple Podcasts, or wherever you listen to your favorite shows.