Can You Hear Sound in Space?


This episode was proudly made possible by
the all-new 2015 Subaru Legacy. It’s not just a sedan, it’s a Subaru. Movies in space are awesome, don’t get me
wrong, except when it comes to the sound. But, if space is a vacuum, then there’s no
sound… but maybe space isn’t a vacuum. Can you hear me DNews fans? Hey, it’s Trace
here and I’m not in space, and if you’re not in space either, then you should be able to
hear me just fine. As regular viewers already know, sound travels using a medium. Sound
is a mechanical, longitudinal wave of energy emanating from a vibration. When a guitar string vibrates, the atoms of
the metal string hit the atoms around it, and that vibration is passed along to the
next and next until it gets to your ear. Once there, the tympanic membrane, or eardrum,
vibrates at the same frequency, and the tiny bones in your middle and inner ear translate
the movement to energy that your brain can interpret. Because all atoms can vibrate like
this, sound can travel through solids, liquids, and gases. Outer space on the other hand, is thought
of as a vacuum, the ABSENCE of matter; and no matter means no sound. But really, in space
it more like, atom, atom… atom… NASA says there’s about one atom per cubic centimeter!
If you took all those free-floating atoms into account, you’d have 90 percent hydrogen,
9 percent helium and less than one percent of other stuff. Which makes sense considering
the makeup of everything we know in the universe, amirite? Even though one atom per cubic centimeter
might seem like more than you thought, it’s still fantastically thin. With such low density, sound’s energy waves
cannot bounce from one atom to another. No atoms, no waves, no sound. So, George Lucas:
you’re wrong!! Spaceships don’t make noise – unless they’re flying within the atmosphere
of a planet… And not just ours! You can hear sounds on certain other planets too.
For instance, sound travels FASTER on Venus than it does on Earth, because its atmosphere
is “thick and soupy,” says Tim Leighton of the University of Southampton. This means
if you COULD talk on Venus, the sound would zoom through your vocal chords, but deepen
in pitch because of the makeup of the air. Basically, you’d sound like a Bassy Smurf. We get around this by building structures
that contain pockets of air. The atmosphere INSIDE the International Space Station sounds
pretty normal. But if an astronaut hit his helmet against something outside, he would
hear the impact because his helmet has air, but the people INSIDE wouldn’t hear anything. Purely hypothetically, if somehow, you could
put your bare head against the outside of the International Space Station you might
be able to “hear” Chris Hadfield inside the ISS playing his guitar. See, that guitar vibration
might travel through the air inside, to the walls of the ISS vibrating them. And then,
if your bones were touching just right, that vibration MIGHT vibrate your BONES and thus
get directly to your inner ear. This is called bone conduction, and it’s used in some headphones
and in tech like Google Glass. Because your bones conduct that vibration, it surpasses
the need for air and doesn’t require the eardrum at all… but again, it would only work if
your bone was touching the ISS. Plus, of course, you’d die pretty quickly… There IS another way to to pull sound directly
from space, not in an atmosphere, or in a spacesuit… can you guess it?
Tell me your guess in the comments! If we get 7,000 likes, I’ll release a follow-up
with the answer! We wanna extend a quick thank you to Subaru, for making this episode possible.
And especially the all-new 2015 Subaru Legacy. Every sedan has its benefits, but only one
combines them all. It’s not just a sedan. It’s a Subaru. Thanks for watching DNews
everyone, and please subscribe.

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