XPost: sci.physics.relativity   
   From: nospam@de-ster.demon.nl   
      
   Arie de Muijnck  wrote:   
      
   > On 2026-02-19 21:41, J. J. Lodder wrote:   
   > > john larkin  wrote:   
   > >   
   > >> On Thu, 19 Feb 2026 20:52:48 +1100, Bill Sloman    
   > >> wrote:   
   > >>   
   > >>> On 19/02/2026 7:49 am, Ross Finlayson wrote:   
   > >>>> On 02/18/2026 12:43 PM, Python wrote:   
   > >>>>> Le 18/02/2026 à 20:13, Ross Finlayson a écrit :   
   > >>>>> ..   
   > >>>>>> and, you know, magnetic monopoles, is widely employed   
   > >>>>>> in medical imaging and the like.   
   > >>>>>   
   > >>>>> No.   
   > >>>>   
   > >>>> Resonance imaging (NMR) is a thoroughly different mechanism   
   > >>>> than Roentgen rays.   
   > >>>   
   > >>> But as the name implies, it's nuclei of the atoms involved that exhibit   
   > >>> the resonance. It's a remarkably low energy effect, and you need   
   > >>> remarkably high magnetic fields to get it to give you a detectable   
   signal.   
   > >>   
   > >> The earth's field is enough. The hydrogen resonance is about 4   
   > >> KHz/gauss.   
   > >   
   > >    
   > >   
   > > (paywalled, unfortunately)   
   > >   
   > > Jan   
   > >   
   >   
   > It's also here in the book in the archive, use a free account to borrow:   
   >   
   >     https://archive.org/details/amateurscientist0000unse_c9s8/   
   age/338/mode/2u   
   p   
   >     the amateur scientist : Free Download, Borrow, and Streaming : Internet   
   Ar   
   chive   
   >   
   >    
   > I prefer the experiment to measure the   
   > earth's magnetic field using MRI.   
   > It is so rewarding to hear that ping after all your trouble.   
      
   Yes, I know. I only gave the paywalled direct link, for the history,   
   because once you know it exists it is easy to find copies elsewhere,   
   (of dubious legality)   
      
   Jan   
      
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