Petrichor, that fresh aroma you can smell after the rain, is caused by a little molecule called geosmin. The name literally means "earth smell." It's produced by soil bacteria and gives an earthy flavour to beets.
Humans are extremely sensitive to this scent – much, much more sensitive than sharks are to blood. Some think we evolved that way to find fresh drinking water after droughts.
@InvaderXan Petrichor is one of my favorite scents in the world.
@InvaderXan Smells are the best, and to know that we are able to sense a smell better than a shark, even with our oft touted pathetic sense of smell, is really good to know.
@SuzanEraslan It's strange really, because mostly we aren't that good at smelling things. But there are a couple of things which we can smell really easily. Another one is the ionones – a group of molecules which cause the smell of roses (though they're also found in a few fruits and vegetables).
@InvaderXan One of the rose ketones! Have you ever read The Emperor of Scent, by any chance?
@InvaderXan It’s about this physicist (among other things) who became obsessed with perfume, then literally wrote the book on it (Perfumes: The Guide), but in doing so may have completely altered the common theory of the mechanism of we smell. It’s fascinating.
@InvaderXan new project; hook up humidifiers to wind turbines in my backyard
since we're on the subject, any ideas on low cost fog/mist reclamation? More the former than the latter, I'm more interesting in capturing stuff in the air before it hits the ground but I haven't been able to find specs on this sort of thing.
@joamo Someone on tumblr told me about a device used in South America called an atrapaniebla, for collecting water from fog. Apparently they're often used for sea mists in Chile.
In English, I think it's called a fog fence? Basically, a big sheet of netting which fog condenses onto. Perhaps that could be what you need?
(Image: Flickr/Nicole Saffie, https://www.flickr.com/photos/26946475@N08/9292245749)
@InvaderXan Yeah! I read about that when some articles were published a while back, but I didn't see a name or specs for it. Is it literally just a net? IIRC the students designed some nifty features into it.
Answered my own question with first page googling: https://watersustainabilityandfogwater.wordpress.com/fog-catchers-and-how-to-make-your-own/
Thanks for the search term
@joamo Anytime! ☀️
As far as I can tell, it's a net with some drainpipe and a water butt to collect any water that condenses.
I'd guess something water repellant like nylon would be ideal. You'd probably need to suspend it carefully so the water runs down where you want it – though be careful if you're making one, as some types of cord shrink slightly when they're wet!
@ChristieMalry This is something I've wondered about social media before. It seems like it might confuse that part of your brain's wiring. Like, which word really was the first? The one I wrote? My username? The post above it in the timeline...?
In short, I wouldn't worry. 😬
@screwjaw Well, the way it works in nature is that on a hot day, the soil gets hot and dry. This kills off the bacteria in it and the dead bacteria dry up and fall apart. Then when the soil gets wet, it releases that sweet, sweet geosmin aroma.
I'm not sure how well you could artificially replicate that though. 😋
@InvaderXan Are humans especially sensitive to geosmin, or are all/most mammals sensitive to it?
@InvaderXan To be fair, we work with them because they're great sources many interesting molecules that we're hoping to turn into new antibiotics. ~70 % of the antibiotics in use today originate from Streptomyces bacteria or close relatives. The nice smell is welcome, but a side effect. 😉
@InvaderXan Antibiotics and resistance will always be an arms race. Microorganisms have been playing this game forever, long before humans discovered antibiotics. But yes, we're trying to find something that works against some of the most dangerous multi-resistant bacteria, to keep up our side of the game.
@InvaderXan You can find ancient bacterial samples (from permafrost soil and the like) that are resistant against antibiotics. As I said, bacteria have been playing the chemical warfare game for quite a while now. We're probably accelerating the resistance formation by using an antibiotic, that's true. But IMHO the cause of the upcoming crisis is that we declared victory in the 70s and stopped a lot of the R&D.
@InvaderXan It certainly is a factor, because it increases the selection pressure on the bad bacteria to become resistant. But resistance itself has always been there. Simply put, the soil bacteria that produce the antibiotic need to be resistant against it, or they'd be committing suicide. It's just that that kind of resistance doesn't matter because in general soil bacteria don't try to eat you.
@InvaderXan The most famous antibiotic (penicillin) was discovered in a mold fungus. But quite a bunch of the other ones come from a small family of bacteria that seem to have a very inventive biochemistry.
I'm biased, of course, but I think it's a super interesting research topic.
Sunbeam City is a solarpunk instance.