Earlier quoted context omitted.
Blood electrocution would get you first. Moving conductor in a magnetic field generates a current, and you'd just need a current big enough to confuse the cardiac nerves. Given that existing MRI research magnets can give weird nervous system feelings when patients wiggle, just an order of magnitude or two more and you'd get knocked out by your own circulating blood.
Don't most of the problems with nerve stimulation in existing MRI systems come from the gradient coils rapidly modulating the magnetic field, rather than people moving around?
How strong would a magnetic field have to be to kill you?
41–50 of 53 posts
Re: How strong would a magnetic field have to be to kill you?
#42Earlier quoted context omitted.
I work in this sector, and what you say is correct, however it is important to note that in TMS the fields are pulsed over millisecond time intervals. In doing so they can induce an electric field which can cause neurons to fire. The time varience is crucial. A 3T static field from the magnet of an MR scanner is far less dangerous than a 1T field pulsed in the vicinity of your brain. That is providing that there aren…
Radiologist here. We regularly image patients in 3T MRI scanners. As long as they don't have certain metal surgical implants, a pacemaker, or metallic foreign bodies, there is no problem. Some institutions have research magnets up to 7T: http://www.healthcare.philips.com/main/products/mri/research...
> there is no problem
We are just beginning to investigative the post operative changes from anaesthesia in adults [1]. Can we be sure that there is no post MRI changes ?
While I'm not suggesting there is any cause for alarm I don't think we should dismiss the possibility out of hand.
[1] http://www.scientificamerican.com/article/hidden-dangers-of-...
Re: How strong would a magnetic field have to be to kill you?
#43Re: How strong would a magnetic field have to be to kill you?
#44Something called Transcranial Magnetic Stimulation alters brain activity at about one Tesla (10,000x earth's field). TMS has been shown to induce euphoria, amnesia, and relieve depression. Unclear what stronger magnetic fields could do. A ten Tesla magnet can levitate a small animal.
http://www.youtube.com/watch?v=A1vyB-O5i6E Not sure if the video is trustworthy, but here's a 97 paper saying 16T can lift a frog http://iopscience.iop.org/0143-0807/18/4/012
http://www.critic.co.nz/columns/article/3703/science-bitches...
Re: How strong would a magnetic field have to be to kill you?
#45The sci-fi book Blingsight by Peter Watts explores humanity's 1st encounter with an alien object that contains extremely powerful magnetic fields. Has all sorts of interesting consequences.
Off-topic, but Blindsight kicks ass on any number of levels. Scientifically plausible vampires! In space! And the only genuinely creepy aliens I think I've ever come across in fiction.
Re: How strong would a magnetic field have to be to kill you?
#46Earlier quoted context omitted.
I work in this sector, and what you say is correct, however it is important to note that in TMS the fields are pulsed over millisecond time intervals. In doing so they can induce an electric field which can cause neurons to fire. The time varience is crucial. A 3T static field from the magnet of an MR scanner is far less dangerous than a 1T field pulsed in the vicinity of your brain. That is providing that there aren…
Radiologist here. We regularly image patients in 3T MRI scanners. As long as they don't have certain metal surgical implants, a pacemaker, or metallic foreign bodies, there is no problem. Some institutions have research magnets up to 7T: http://www.healthcare.philips.com/main/products/mri/research...
tattoos can be a problem, right?
Re: How strong would a magnetic field have to be to kill you?
#47I think that you'd end up with neurological effects before the electrons were ripped out of atoms. I mean, our nervous system is effectively controlled ionic exchange.
Here's a video of someone braver than myself experimenting with the effects of magnetism on his brain while he speaks: https://www.youtube.com/watch?v=XJtNPqCj-iA
First this is borderline mad, the shocks sound nasty, second it seems to me that more than speech is impacted, his whole face stutters.
Re: How strong would a magnetic field have to be to kill you?
#48Radiologist/Biomedical Engineer here. I once did a review of the physiological effects of magnetic fields as was our current understanding in the last decade. in general, things that get altered with sufficiently large magnetic fields:
- Cardiac electrical conductivity
- Muscular electrical conductivity
- Fibrin (protein necessary for clotting blood) meshes get distorted
- There is DNA genotoxicity, and mutations start to appear
- Diamagnetic effects start taking over (Most extreme demonstration I've seen so far is the levitating frogs and grasshoppers, which seem quite content afterwards, so no ill effects apparent)
Bottom line is that pretty much everything in our bodies that contains water can be affected by a sufficiently large static magnetic field. Some critical physiological processes may get disrupted way earlier than the atomic distortions cited in the article, so I believe much less than 100k Tesla would be needed to kill a person.
Re: How strong would a magnetic field have to be to kill you?
#49I've always wondered what would happen if you got trapped in the Superconducting Super Collider.
Terminator 3 Particle Accelerator Scene
Re: How strong would a magnetic field have to be to kill you?
#50Earlier quoted context omitted.
Radiologist here. We regularly image patients in 3T MRI scanners. As long as they don't have certain metal surgical implants, a pacemaker, or metallic foreign bodies, there is no problem. Some institutions have research magnets up to 7T: http://www.healthcare.philips.com/main/products/mri/research...
tattoos can be a problem, right?
Yes, certain inks contain enough metal to cause significant tissue heating.