22 ms·
How strong would a magnetic field have to be to kill you?
- Sniffnoy 5y agoThis links to a comment on the blog post, rather than the blog post itself. The link should be https://gravityandlevity.wordpress.com/2015/01/12/how-strong-would-a-magnetic-field-have-to-be-to-kill-you/ https://gravityandlevity.wordpress.com/2015/01/12/how-strong...
- Animats 5y agoMice have been levitated in a 16 tesla field and survived.
- btilly 5y agoFrogs likewise. See https://www.ru.nl/hfml/research/levitation/diamagnetic-levitation/ https://www.ru.nl/hfml/research/levitation/diamagnetic-levit.... This achievement won the Ig Nobel prize for Andre Geim. A decade later he won the Nobel prize for discovering how to create graphene using scotch tape: https://www.improbable.com/2010/10/05/geim-becomes-first-nobel-ig-nobel-winner/ https://www.improbable.com/2010/10/05/geim-becomes-first-nob.... As far as I know he remains the only person to win both prizes. An interesting side note is that neither piece of research was what his lab was supposed to be working on. He established a tradition of Friday Night wacky experiments on stuff that had nothing to do with his lab's official business, in areas of science that they knew little about.
- modeless 5y ago> he remains the only person to win both prizes Wow, if I was a scientist this would definitely be my new life goal. I love the comments on the levitation page under "Why did you use a frog?"
- huachimingo 5y agoSo cool, nice ideas often come from serendipity or saying "yeah why not if..."
- 0x0203 5y agoSome video of the levitating frogs, and a few other things: https://www.youtube.com/watch?v=KlJsVqc0ywM https://www.youtube.com/watch?v=KlJsVqc0ywM
- codetheweb 5y agoReminds me of What If? from Randall Monroe. https://what-if.xkcd.com https://what-if.xkcd.com
- rodolphoarruda 5y agoThis book is pure entertainment. I bought the ebook by impulse not knowing exactly what it was about. Reading it was a surprising joy.
- bobbles 5y agoIt's shame that after that entire explanation (the moon-earth firepole one) that he never actually answers the question of how long it would take...
- saagarjha 5y agoMost of the time goes into climbing, which he estimates as taking "several years".
- LorenPechtel 5y agoYou can't climb the pole. Tsiolkovsky's rocket equation rules, you can't bring enough food to climb the pole. (Yes, I know, it's not a rocket. It really should be called Tsiolkovsky's logistics equation--it applies to any situation where you have to bring along your power source, whether it's a rocket or not.)
- Sohcahtoa82 5y agoReally? I must be misunderstanding something then. The Earth-Moon L1 point is ~63 km from the Moon. Let's say me and my gear weigh 200 lbs, and the Moon's gravity acceleration is 1.62 m/s^2. 63 km * 200 lbs * 1.62 m/s^2 gives a potential energy of only 2,213 kcal. The human body is only 18-26% efficient [0] at converting food into energy, so we're probably looking at around 10-13,000 calories. Depending on what you're eating, that's 4-10 lbs of food. Obviously, I'm ignoring the time it would take to climb that far, but in terms of energy, it seems reasonable that a human could carry enough good with them, unless I'm gravely misunderstanding something. I'm guess that assuming "potential energy" means "the energy needed to move X pounds to Y height at Z gravity" is incorrect. [0] https://physics.stackexchange.com/questions/46788/how-efficient-is-the-human-body https://physics.stackexchange.com/questions/46788/how-effici...
- version_five 5y agoAn MRI machine has a very uniform field inside the magnet, and a very strong gradient outside as the field curls back on itself. If you move your head back and forth outside the end of the bore, it causes dizziness, by inducing eddy currents in the brain (I've not done it myself, I'm very risk averse, but I've seen others doing it). I'd be much more worried about moving through a very strong gradient, spatially or temporally, than about the absolute field strength. Human made sustained field strengths are generally not dangerous, if the field is uniform. For example there is human and animal imaging at 7T , although lower field strengths are more common (the limiting factor, other than making the static field, is generally the RF frequency, which gets higher with field strength and introduces other issues as it does)
- goldenkey 5y agoYeah, this question is akin to: how strong a gravitational field would you have to be in, to kill you? Well, you could be in a gravitational field of 10^12548125971 Newtons, you wouldn't feel anything though, you would be weightless. It's the Spaghettification [1] that can hurt you, and that's due to the gradient in the field, not the actual field strength. Thank you for your comment. [1] https://en.wikipedia.org/wiki/Spaghettification https://en.wikipedia.org/wiki/Spaghettification
- vikingerik 5y agoIt's not the same question, and that's the point of this article. Gravity acts equally on all your particles, so it doesn't cause any disruption (other than that gradient.) Magnetism affects different particles differently, particularly moving ones, as in electrons. The article says how a strong field compresses and deforms electron orbitals, to the point where covalent bonds fail. Field strength alone causes that, not gradient.
- BizarroLand 5y agoI don't know if we could measure the difference, but since gravity's force decreases with distance, I bet there is a difference between the gravity on the top of your head vs the bottom of your feet. It's probably small enough to be negligible, but it should be there.
- soheil 5y agoLong before orbits of electrons around atoms are affected the iron in the blood will get concentrated due to the strong magnetic field and cause blood clot and death from brain stroke.
- drdeca 5y agoI thought hemoglobin wasn’t ferromagnetic?
- heisenzombie 5y agoHere are some slides from a talk I heard on the topic (warning, PowerPoint) by a CERN magnet scientist: https://indico.bnl.gov/event/609/contributions/15418/attachments/13763/16843/Buzio_-_Safety_and_health_impact_of_magnetic_field.pptx https://indico.bnl.gov/event/609/contributions/15418/attachm... There's some great stuff in there! Like calculating a 3% increase in systolic blood pressure due to magnetic drag at 8T. One of the main takeaways is that DC fields are most likely to kill you because of a fast-moving screwdriver that someone left nearby. By contrast, AC fields --- or moving in non-uniform DC fields --- can be more dangerous. Apart from mechanical (flying screwdrivers) or electrical (fires in the bus-bars) hazards, he indicated that the most common hazard occurred when technicians put their head into/near a very high-field magnet: This affects parts of the "inner ear" vestibular system and therefore causes dizziness/vertigo. In short: They could fall over!
- BrandoElFollito 5y agoAs a CERN summer student in 1993, I remember we had a very similar presentation. This is not surprising that CERN is that knowledgable about extreme magnetic fields given how hard it is to deviate the beams.
- mikewarot 5y agoIf the fringe theory of microtubules storing memories in quantum states in the human brain is correct, there is a critical magnetic field past which you'd forget everything... including the things you learned in infancy, like how to hold your head up, crawl, talk, etc. I suspect that critical field would be somewhere near 1000 Tesla, as the critical temperature is well above 2000k. (The theory is that memories are stored in a topological superconductor which would denature well before the critical temperature was reached) This type of reversion to infancy is the stuff of nightmares.
- mhh__ 5y agoThanks to the CIA's extremely vital work in the 1960s (MKUltra), there apparently has been research into this... http://www.ect.org/dr-camerons-casualties/ http://www.ect.org/dr-camerons-casualties/ e.g. using a tape loop to encourage people to forget who their parents are. Ethics is important.
- niea_11 5y agoArchived copy from 2008 : https://web.archive.org/web/20080223080510/http://www.ect.org/dr-camerons-casualties/ https://web.archive.org/web/20080223080510/http://www.ect.or... (I have a php error with the direct url)
- jasonladuke0311 5y ago> If the fringe theory of microtubules storing memories in quantum states in the human brain is correct, there is a critical magnetic field past which you'd forget everything... including the things you learned in infancy, like how to hold your head up, crawl, talk, etc. This was a plot point in one of my favorite sci-fi books [0]. I thought it was totally made up for the book. [0] https://www.goodreads.com/book/show/33413556-the-gone-world https://www.goodreads.com/book/show/33413556-the-gone-world
- EGreg 5y agoFunny enough, 5G (electromagnetic waves) are enough to cause DNA damage in cells, but your skin prevents a lot of them from getting in. Presumably the skin cells themselves are shed before they mutate I guess? Anyway, agencies of the WHO have labeled EMF “potentially carcinogenic”. Here is from 2019: https://blogs.scientificamerican.com/observations/we-have-no-reason-to-believe-5g-is-safe/ https://blogs.scientificamerican.com/observations/we-have-no... (Scientific American) Yet the capitalist industry pushes it into all the cities now, so we’ll be surrounded by It on every city block. The skin is the only reason the cells inside humans and pets are safe from all this EM radiation. Here are a few references: https://www.nature.com/articles/s41370-021-00297-6 https://www.nature.com/articles/s41370-021-00297-6 (Nature Magazine 2020) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6765906/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6765906/ (National Institutes of Health) This is not the case for insects, though, as their epithelial cels do not form such a protective barrier. I would not be surprised if cellphone towers, wifi and other radiomagnetic waves are killing off the insects around cities. Their skin doesn’t actually block all those waves! PS: I am not an expert, but is the 5G for cellphone mini towers the same as the 5G for wifi networks? Because we have been around those for a decade now. EDIT: Why all the downvotes? This is relevant basic information that not everyone here knows, with references to mainstream publications that go more in depth for anyone who is interested.
- drdeca 5y agoThe blog post is about magnetic fields, not EM radiation.
- EGreg 5y agoElectromagnetic radiation consists of waves of an electromagnetic field. What I wrote is directly relevant to the topic, and is also something that has is currently being put into place around the country so it also connects the topic to what’s actually going on. https://en.wikipedia.org/wiki/Electromagnetic_radiation https://en.wikipedia.org/wiki/Electromagnetic_radiation As usual - if you don’t like something, simply disagree on the substance. I am happy to be corrected on anything I may have misstated.
- endisneigh 5y agoWhat would happen to your hand if you hand a hand size MRI machine and stuck your hand through? Would it in anyway disable your hand?
- mhh__ 5y agoI remember looking up a paper (something I guarantee they never did...) some 5G nut linked to me, one of the studies used was trying to show that shoving a mouse in what was effectively an MRI machine did something - this is obviously totally dissimilar to a 5G signal. The interesting thing is that some of these studies (biology p-values keep in mind, though) did show an effect of somewhat realistic microwaves. What's the catch? That doesn't mean this effect poses any risk beyond possibly existing at all.
- nullc 5y agoMagnetic field != gradient of magnetic field. Changes in fields induce currents, you can stop your heart or cause seizures with enough currents in the wrong places. Field from a magnet falls off with the inverse cube of distance... so "I was somewhere near an insanely powerful magnet" isn't really saying much. In an MRI you're probably more likely to see effects of heating from the excitation RF-- which is multiple kilowatts of UHF for 1.5T magnets, and scales with the field strength.
- ta988 5y agoYes the pulsed fields can definitively cook you. It is often a limiting factor in saturation experiments (used to hide a signal in a sample to increase dynamic range) that increases experimental time. I've seen solvents boiling in samples analyzed in NMR magnets. And it usually messes up your experiments way before that anyway because temperature make some of the signals shift in the spectrum you acquire.
- mlang23 5y agoSomewhat related anecdote: Roughly 20 years ago, I took part in a scientific experiment which aimed to confirm a theory that in blind individuals, parts of the formally vision-related parts of the brain are involved in reading tactile braille. The experiment itself was pretty interesting, since it was conducted in an fMRI machine. Back then, the f in fMRI was sort of the new thing. I was used to a yearly MRI checkup, so this is why I volunteered. It wasnt particularily relaxing, as every session took roughly 3 hours. They tailor-made a helmet from gypsum so that my head wouldnt move at all. My compensation for all of this was clearly not the money (which was too little to remember), but the relaxed chat with the lead brain researcher and the MRI technicians during and after the experiment. At the time, the magnetic field strength of the fMRI I was getting was the highest I ever received. I was used to MRI around 0.5 tesla. During the experiment, I was getting 3 tesla. And I was feeling a strange sort of shiver going down and up my spine. They were experimental imaging people, so I took the opportunity to chat about the fonrtier of healthyness. MRI has this air of "you dont feel it and it cant hurt you". I still believe around 3 tesla can be perceived slightly by your body. I have received higher magnetic field strength in normal medical settings since, and sometimes I can feel that shiver. Anyway, as we were chatting about tesla, the scientist dropped quite casually. "At 11 a mouse is cooking." So much about boundaries. I never asked him if they know because they tried :-)
- ta988 5y agoI've worked with 21T magnets (NMR), the head just in the unshielded parts of it (you cant really get your head inside these as the bore size is small but you are right where the field lines start to bend). Never noticed anything. Colleagues working on larger bore but lower field magnets told me that moving their head fast around them was making them feel weird.
- logifail 5y agoBack in the day I spent the best part of three years working with NMR machines pretty much on a daily basis, also never noticed any physical effects. Once I almost had a magnet snatch my bunch of lab keys out of my hand, having forgotten the cardinal rule to "leave all magnetic materials at the desk before you approach the magnet with your sample tube"... Heard a joke about the children of NMR staffers having atypical sex ratio, but that was just student humour. I think :)
- thwoeru23432 5y agoSince neuronal-signal transmission does not actually transport ions in the direction of information travel (unlike electrons in circuits), this is not too surprising ?
- oblak 5y agoFunny, isn't it? The human was impervious to our most powerful magnetic fields, yet in the end he succumbed to a harmless sharpened stick!
- bryanrasmussen 5y agoI always found that story highly implausible, somehow this alien monster - the 'human' - has evolved a defense against one of the things that binds all life together but has a fatal weakness towards something otherwise innocuous, and it has traveled through space to the one planet where its weakness can be found! It is just a hackneyed updating of the myth of Rolnak of the three stones, only with a sharpened stick taking the place of fire. I guess some crafters of tale care more about the money than coherence in the tale.
- jamesrom 5y agoI can’t tell if you’re being serious. https://tvtropes.org/pmwiki/pmwiki.php/Main/Mundangerous https://tvtropes.org/pmwiki/pmwiki.php/Main/Mundangerous
- formerly_proven 5y agoThis is sort of like asking what the lethal dose of neutrinos is.
- WJW 5y agoDon't leave us hanging like that. What IS the lethal dose of neutrinos?
- MauranKilom 5y agohttps://what-if.xkcd.com/73/ https://what-if.xkcd.com/73/
- jeroenhd 5y agoI think it's a question worth answering simply because there are people out there who fear magnetic fields, be they from power lines, electromagnetic transmitters or otherwise. I've seen the effects of magnetic fields referred to in several posts from people trying to prove that Chinese 5G bats are causing covid. Some basic research and napkin math to show people they have nothing to fear might be useful, although I'm not sure how far you'd get in a discussion with people that firmly believe in such nonsense. I'm also kind of curious what the lethal dose of neutrinos would be. I know humanity will be burned to a crisp by an exploding sun before a neutrino overdose would ever become a problem, but if there's a theoretical deadly dose I'd be interested to know it.
- DebtDeflation 5y agohttps://en.wikipedia.org/wiki/Magnetar https://en.wikipedia.org/wiki/Magnetar The magnetic field of a magnetar could kill a human from 1,000KM away.
- WJW 5y agoI'm pretty sure coming within 1000 KM of any neutron star is pretty dangerous due to https://en.wikipedia.org/wiki/Spaghettification https://en.wikipedia.org/wiki/Spaghettification
- raxxorrax 5y agoYou would probably already be pesto from radiation anyway even before you reaech spaghettification.
- Wolfenstein98k 5y agoOP link points to a comment instead of the article itself.
- omnicognate 5y ago> Normally, these little electron orbits all point in more or less random directions. But in the presence of a strong enough external magnetic field, the electron orbit will tend to get aligned so that its “north pole” points in the same direction as the magnetic field. By my estimate, this would happen at a few hundred Tesla. Isn't this exactly what happens in an MRI machine?
- pvaldes 5y agoI would fear more a mechanical damage than DNA mutation. Even relatively small neodymium magnetos can crush easily a finger.