The Hum

I sit on the back deck watching over my plants because I believe if they aren't growing well it's because they need attention.  It's a poor excuse for wanting to sit on the back deck, alone, and just observe.  There's a constant hum even if cars aren't barreling down Kimball with their mufflers scuffing the pavement or their traditional Hispanic meringues swinging back and forth with the bass... buum... bauum... buum... bauum... Aside from the squeaking buses squealing to a stop and the high pitched beep as they decompress the front right side of their carriage to let tiny-legged or physically challenged people off, there's a hum.
When everything is supposedly silent, in the middle of the night, the hum persists.  I don't know exactly what it is, but I hear it.  It's almost like a white noise phenomenon whereas you hear it so often that your brain chooses not to hear it.  But that hum persists. 
On tranquil nights, or however you define a tranquil night in Chicago, we'll be watching the sky, hoping for stars, getting extremely excited to see one then two, and our eyes adjust, three-woah-six stars in the sky like we're floating down the Columbia River star gazing beneath an illuminated bed sheet spread over the boat like a fort. (A floating fort!), that hum still persists. 
It sounds like a finely tuned German generator powering the city and rotating beneath us at six thousand RPMs, delicate and soft, like GE designed it to, but alas it's not-or, at least I hope it's not because that would really disturb my sense of reality.
It's the indefinable hum of the city.
Now, I know indefinable is blasphemy in this day in age and I'm sure the challenge would be met with a lot of answers or theories or suggestions as to what the hum is, but I guess I just don't care about those right now.  I guess I would just like to recognize the hum and write about recognizing it.  I'm a gypsy and I'm not a hippie.  I've dabbled in Buddhism and read some Kerouac, but this isn't existential.  In fact, I would say it's just a hum. 
I could try to persuade you that the hum represents a bustling Chicago, but all my friends go to sleep at night.  In my world, in my head, the hum is explicable only by theorizing why it's there.  And that's exhausting.
Sometimes, it's interesting if you have a unique idea like the government is flying drones over the city at night and dropping miniscule particles of aluminum which seep into our skin and acts as a tracking device so they know where we are at all the time.  Cool.  If you believe that and want to go Edward Snowden about revealing or uncovering it then that's great.  All I'm saying is that I don't care.  I get it.  It makes sense.  If I don't know what is happening then what's the goddamned difference?  The statement is sacrilege in our generation, I know. 
But, we're all willingly being tracked by our cellphones anyway so, really, what's the difference?