Could You Hear In Space?

Sound needs matter to travel through -- and matter is scattered pretty far and wide in space. Learn more about how hearing works and how space works in this episode of BrainStuff, based on this article: https://science.howstuffworks.com/humans-hear-in-space.htm/printable

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Episode Transcript

Speaker 1 (00:01):
Welcome to Brainstuff, a production of iHeartRadio, Hey brain Stuff,
Lauren Vogelbaum. Here You're sitting in a movie theater watching
the latest sci fi action film. The screen is filled
with an intense space battle. The theater booms with other
worldly noises. Is ship engines roar and wine, A laser's

(00:23):
hum in your seat rumbles? Is? Spacecraft explode left and right?
But if you were really able to watch the battle
in person, would you be able to hear anything at all?
If we look to science fiction films for the answer,
we get conflicting results. The tagline for the film Alien
was in space, no one can hear you scream, but
the film actually depicts noisy spaceships. A few examples, like

(00:46):
the film two thousand and one, A Space Odyssey and
the TV series Firefly have silent space scenes, but it's
more common in space fiction, like most of Star Wars
and Star Trek, to have dozens of scenes that combine
action and outer space with nifty sound effects. So which
fictional universe should we believe? Would you be unable to
hear the Enterprise if zipped right past you? Would the

(01:08):
destruction of the Death Star be completely silent? To get
to the bottom of this question, we need to look
at two important factors, how sound travels and what's actually
out there in space. A sound travels in mechanical waves.
A mechanical wave is a disturbance that moves and transports
energy from one place to another through a medium. In sound,

(01:31):
the disturbance is a vibration, and the medium can be
any series of interconnected and interactive particles. That means that
sound can travel through gases, liquids, and solids. For example,
imagine a church bell. When a bell rings, it vibrates,
a meaning the bell itself flexes inward and outward very rapidly.

(01:53):
As the bell moves outward, it pushes against the bits
of air immediately surrounding it. As we've talked about on
the show, air might seem like nothing to us, but
it's actually a sort of soup of particles and molecules.
So those air bits touching the bell then push against
other adjacent air bits and so on. Then, as the

(02:14):
bell flexes inward, it pulls against the adjacent air particles,
and they in turn pull against other air particles. This
push and pull pattern is a sound wave. The vibrating
bell is the original disturbance, and the air particles are
the medium through which the vibration travels. But sound isn't
restricted to moving through the air. Let's say you press

(02:36):
your ear against a solid surface like a table and
close your eyes. Then someone taps their finger at the
other end of the table. The tapping becomes the initial disturbance.
Each tap sends vibrations through the table, and the particles
in the table collide with each other and become the
medium for the sound wave. The particles and table collide
with the rim of your ear, so you might feel

(02:57):
the vibration in your ear or the rest of your head,
But they'll also collide with air particles trapped between the
table and your ear drum inside your ear. The ear
drum is also known as your ear's tympanic membrane. When
air particles hit it, this sets off a series of
vibrations in several structures inside the ear. The brain interprets
these vibrations as sounds. Basically, how hearing works is a

(03:21):
different episode. Okay, so sound needs a physical medium in
order to travel anywhere. Is there enough physical material in
space to act as a medium for sound waves. Before
we begin to talk about space, we should probably define
it because there's a lot of it out there and
it's not uniform. For the purposes of this discussion, will

(03:42):
consider space to be the region of the universe outside
of Earth's atmosphere. You've probably heard that space is a vacuum.
A true vacuum refers to the complete absence of matter,
but space contains stars, planets, asteroids, moons, comets, dust, which
is all a lot of matter. But space is still
considered a vacuum, or technically a near vacuum because space

(04:06):
is big of planets can be millions of miles apart,
and solar systems can have billions of miles between them.
This empty space, sometimes called interstellar space, is practically devoid
of all matter, and again, sound waves can only travel
through matter. In interstellar space, the distance between particles is
so great that they would never collide with each other.

(04:28):
Even if you could get a front seat for the
explosion of the dust star, you wouldn't hear anything at all.
That being said, there are a few arguments one could make.
Radio waves can travel through space. So if you're wearing
a space suit that contains a radio unit and one
of your buddies sends you a radio message there is
fresh pizza in the space station. You'd be able to

(04:50):
hear it. That's because radio waves aren't mechanical, they're electromagnetic.
Electromagnetic waves can transmit energy through a vacuum. Once your
radio receives a signal, it can convert it into sound,
which will travel through the air in your spacesuit without
a problem. Or let's say that you're drifting through space
while wearing a spacesuit and you accidentally bump your helmet

(05:12):
into the Hubble space telescope. The collision would make a
sound that you could hear even though you're in space.
That's because the sound waves would have a physical medium
to move through your helmet and the air inside your spacesuit.
You'd still be surrounded by a vacuum, so an independent
observer wouldn't be able to hear anything, no matter how
many times you had but a satellite. Or imagine you're

(05:34):
an astronaut on a mission at the International Space Station.
You've decided to step out into space, but forgot to
put on your spacesuit first. You press your ear against
the station, you won't have any air in your ear,
so you couldn't hear In the traditional sense. However, you
make out a few sounds through bone conduction, in which
sound waves travel through the bones of the jaw and

(05:55):
skull to the inner ear bypassing the ear drum. There's
no need for air, so you could hear your fellow
astronauts partying inside the shuttle for about fifteen seconds. After that,
you'd likely be unconscious and on your way to dead.
So yes, despite the wisdom of Hollywood filmmakers, it's impossible
to hear noises in space. We suggest the next time

(06:18):
that you watch a science fiction film you plug your
ears up whenever anything happens within the vacuum of space.
It'll make the film seem more realistic and probably work
as a great conversational topic with your friends once the
movie's over. Today's episode is based on the article can
humans here in Space? On how stuffworks dot com written
by Jonathan Strickland. Brainstuff is production of iHeartRadio in partnership

(06:41):
with how stuffworks dot Com, and it's produced by Tyler Klang.
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