Quieting the Global Growl • Hacker News Board

Re: Quieting the Global Growl

#51

Post by genter » Sat, Jun 08, 2024, 2:57 AM UTC

marssaxman wrote: post #32

spinach wrote: post #21

Earlier quoted context omitted.

Humans in cities have also got used to the noise. Go from a quiet forest or rural area in the middle of nowhere to a city or residential area where you have cars, trains, lawn mowers, leaf blowers, air planes, loud barking dogs, etc. It's shockingly noisy. It's surprising that people don't want to do more about the noise pollution but it seems many just got used to it.

Rural areas can be noisy, too, depending on the ecosystem: birds, frogs, crickets, and cicadas can all kick up quite a ruckus. One can get used to just about anything.

I've yet to hear an animal so loud that the walls of my house shake. My neighbors car can do it no problem.

Re: Quieting the Global Growl

#52

Post by pants2 » Sat, Jun 08, 2024, 4:28 AM UTC

mycologos wrote: post #26

If you're a layperson interested in these sensory questions, I highly recommend the book An Immense World by Ed Yong. It's a 400-something page tour through the many senses animals have and we (mostly) don't. It might have the highest density of truly cool animal facts per page of anything I've ever read, despite being written for adults who maybe haven't considered themselves the audience for fun animal facts in dec…

I'll have to check this out. I thoroughly enjoyed Sensory Exotica by Howard Hughes which does a deep dive into four extraordinary senses: biosonar, biological compasses, electroperception, and chemical communication

Re: Quieting the Global Growl

#53

Post by mycologos » Sat, Jun 08, 2024, 3:55 PM UTC

cactusplant7374 wrote: post #33

mycologos wrote: post #26

If you're a layperson interested in these sensory questions, I highly recommend the book An Immense World by Ed Yong. It's a 400-something page tour through the many senses animals have and we (mostly) don't. It might have the highest density of truly cool animal facts per page of anything I've ever read, despite being written for adults who maybe haven't considered themselves the audience for fun animal facts in dec…

Which fact did you find the most interesting?

"Most" is pretty hard, so I'll just pick one I think is good. I'm paraphrasing here, so errors are mine.

Sea otters, which feed themselves through long dives to and from the ocean floor, with a blind and hurried pawing for urchins in the middle, have hands that are about as sensitive as human hands, but significantly faster. Tasked with distinguishing boards with slightly different small ridges, humans compare and re-compare before deciding; if an otter touches the correct board first, it doesn’t touch the second one at all. This is true even though a human fingertip, if inflated to the size of the earth, is sensitive enough to distinguish between cars and houses. A manatee’s face is about as good.

Re: Quieting the Global Growl

#54

Post by sevensor » Mon, Jun 10, 2024, 4:35 PM UTC

dredmorbius wrote: post #49

sevensor wrote: post #12

Earlier quoted context omitted.

I'm not a fluid mechanics guy, but all that cavitation from the screws seems like preventably wasted energy, not to mention a huge source of potential surface wear.

Correct on both counts. Nuclear submarines feature very large, many-bladed, specially-shaped propellers often turning very slowly to reduce both noise and wear (though more the former: stealth is key to submarine operations). Cavitation on hydraulic and steam turbines, as well as other hydraulic mechanisms, is a major source of wear and failure. Keep in mind that cavitation is equivalent to boiling, and involves both…

Fascinating, thank you!