Magnetic Effects

Robert Harman rmharman at jhunix.hcf.jhu.edu
Sun Mar 2 02:30:32 EST 1997


Douglas Rand (drand at sgi.com) wrote:
: What *is* emitted by the aligned electrons (I believe it's just the
: hydrogen atoms,  but my chem. courses are about 20 years ago) are radio
: frequency radiation.  That's picked up by very sensitive detectors and
: turned back into a 3d map.  There's no ionizing radiation involved at
: all.

Physics recall: atoms have electron shells.  Applying energy to an atom
causes its atoms to hop up to higher shells, and when they fall back they
release photons at characteristic frequencies, based on the difference in
energy level between shells.

Strictly speaking the radio frequency waves were produced as a sort
of low frequency ionizing radiation, but the kind of atoms whose electron
shells would allow for high frequency emissions (like gamma rays) don't
exist in significant quantities in the human body.  (I worked over last
summer in the NMR lab at Bayview Medical Center in Baltimore, doing an
analysis of NMR in systems undergoing complex chemical exchange.  I'm
secondary author on a paper on the subject that should be published by the
end of this year.)

: For the curious: As I remember this,  gamma radiation is defined as
: radiation from nuclear events and things like particle destruction.

Yeah, that'd be one source.  Gamma rays are just ultra-high frequency
photons.  Compared to alpha or beta radiation, they're pretty harmless.
Which is a good thing, given the fact that we're bathed in them pretty
constantly by sunlight.

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|     R Michael Harman, Student of Omniscience     |
| rmharman at jhu.edu ---- talk r at jhu0253.res.jhu.edu |
|       http://jhunix.hcf.jhu.edu/~rmharman/       |
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