I've heard that vacuum cleaners can easily be made to run quietly, and are in Europe, but in America the quiet ones don't sell because we think they can't possibly be doing anything. I still like the sound of a vacuum cleaner. It reminds me of innocent youth and a mommy who loved me very much, just not enough to put a sweater on me.
What they really mean is that there's no sound in a place with nothing in it, because there's no medium for the sound wave to travel through. You need Stuff for sound to wobble around in. Like dust in a vacuum cleaner bag. Or, you know, air molecules. So sound is produced by a pressure wave moving through a medium. ("I summon the ghost of Juliet's grandmother," it might say.)
And that means it's very quiet in deep space. Once you've slipped the surly bonds of Earth (all the noise makes it grumpy) and there's nothing to bounce light off of or prod into a wave pattern, it goes black and silent. It's only because we're living inside a layer of planet-batting that we can hear anything.
The sun should have that looked at.
When I was little, the neighbor man asked me: if a tree fell in the forest and nobody was there to hear it, did it make a sound? He wanted me to get existentially challenged thinking about it, and he was all ready to pounce and say "But how would you know?" as soon as I made either choice, but instead I said "Well, I guess it depends on if you're thinking of the sound as something the falling tree makes, or it's something we hear in our ears," and I think that answer made him grumpy. The thing about the tree is that if it fell in a forest containing no air--and it would, trees need air--it would not make a sound, except through the molecules in the ground it hit.
Anyway, the universe is full of potentially noisy items that we could hear the hell out of if only there were air, so it's just as well there isn't. Still, I like to scrunch up small and look at the sky and imagine it humming and crackling and farting and making great hoots of celestial laughter. Why not? Makes me warm.