So, in space, no one can hear you scream, right? Correct! Sort of..
Sound requires a medium such as air to move through so we can hear it, but acoustic sound (what we hear) is different from wavelength sounds. Now, generalizing all of sound into the term “wavelengths” will have scientists and audio engineers beat me up, so let me explain. Wavelengths vary in size, depending on spatial distance (the distance over which a wave’s shape repeats), and depending on that distance, it is classified into different categories. Microwaves, Visible light, X-Rays, Gamma Rays and more. Staying on the original topic, I wont be discussing specific wavelengths any more (as best I can) but here’s the list:
What can you hear in space? Nothing.
What can science hear in space? Everything.
Everything makes sound from resonating frequencies, and if something is moving in any direction, whether it moves from gravitational force or is put into motion from another object (collision with something, or projected medium from explosion), or aliens. Earth makes sound, the moon makes a sound, the sun makes sound, and atoms themselves make a sound. Anyone who has a HAM radio can hear Earth’s sound; it tends to sound like wind blowing in a storm with birds chirping. The sun tends to sound like a roaring fire and thunder (who’d have thought?), and the moon resonates at a pretty standard frequency giving a hum, but not much else. Henry over at Minute Physics used Hydrogen and pitch shifted the frequency down to a tone humans can hear unaided, and it was.. creepy. An ominous hum that was constant.