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Detecting Methane from Miles Away
- craftyguy 9y agoWell, that's a terrifying device for finding humans.
- candiodari 9y agoTerminator: a thousand humans. Tracking. Terminator: Acquiring target. Distance 200m. 150m 100m 50m Cow: MOOOOOOOOOO! Terminator struggles 30 seconds to eject head from cow butt.
- skocznymroczny 9y agohttps://en.wikipedia.org/wiki/People_sniffer https://en.wikipedia.org/wiki/People_sniffer
- GoToRO 9y agoIt seems that you also need to install mirrors in the area you want to check. So it really is a system and not a device.
- eeZah7Ux 9y agoIt also has a slightly cyberpunk look that helps: https://cires.colorado.edu/sites/default/files/mathaneinstrument.jpg https://cires.colorado.edu/sites/default/files/mathaneinstru...
- meatsock 9y agoheadline should read "a mile away" also i don't think that methane comes out when a human exhales.
- amelius 9y agoPerhaps a tiny fraction, and that's detected (?)
- simias 9y agoI'm not entirely sure about it but I guess they used "human exhalation" as a somewhat relatable unit of volume for a gas but the actual system has nothing to do with detecting humans? That's the only way that makes sense to me, although if that's the case that's really needlessly confusing.
- teddyh 9y agoSince humans don’t exhale methane, it’s weird of the article to use “¼ of a human exhalation” as a measure of volume.
- jonsen 9y agoI think it's fine. It's a measure of gas flow I can relate to.
- adventured 9y agoThey do, in very trace amounts. The exhalation of inflated amounts of methane during a breath test is actually often an indication of a malabsorption syndrome.
- tischler 9y agoThey do, but at the other end.
- anonytrary 9y agoI think they missed a great title opportunity. A "fart detector that works a mile away" seems to be great way to phrase it; it's concise, easy to imagine, relatable and comical. The article could then go into the specifics of what the detector actually picks up (e.g. CH4). I find the diffusion of the smell of flatulence to be a better comparison, because it invokes a visceral reaction ("eww", "yuck", etc.). Imagining a device which does this seems easier. I have a worse idea of what "1/4 of a human exhalation" means.
- gsaga 9y agoAnd the comment of the year award goes to...
- evrydayhustling 9y agoUnfortunately for the fart detector (but fortunately for us!), human farts average around 100ml [1], whereas an adult male breath averages about 500ml [2]. That could still be sorted out for your title, but we also have to consider that a fart is only about 7% methane [3]. This suggests the one mile sensitivity is going to be at around 18 simultaneous average farts, or 5 at the record-breaking end of the scale -- conditions which might indeed justify further surveying the region at altitude. If we're willing to get closer than a mile (questionable in the above scenario), we can apply an inverse law for gas diffusion [4] (I was surprised it wasn't inverse square!) and find that the apparatus can can detect a single average fart at a distance of around 30 feet -- easily covering most elementary school classrooms and automating away the "whom smelt it dealt it" dilemma. [1] https://www.chemistryworld.com/news/explainer-the-chemistry-of-farts/2500168.article https://www.chemistryworld.com/news/explainer-the-chemistry-... [2] https://en.wikipedia.org/wiki/Tidal_volume https://en.wikipedia.org/wiki/Tidal_volume [3] https://en.wikipedia.org/wiki/Flatulence https://en.wikipedia.org/wiki/Flatulence [4] https://physics.stackexchange.com/questions/290059/inverse-square-law-equivalent-for-concentration https://physics.stackexchange.com/questions/290059/inverse-s...
- stevespang 9y agoThe military could grab this and use Co2 exhalations to detect hidden enemy soldiers. I can't wait to see a vid on YouTube showing a field of cows with their back ends "lighting up" every few minutes. But maybe some prankster will just create something simpler like a strap on igniter that pulses a spark every second or so, but does not shock the cow. Then one could observe a night time show.