IAU thesaurus in RDF (an update)

[Arnold Rots]

This hit a nerve: the 21 cm hyperfine line of neutral atomic hydrogen
is NOT a recombination line.

  - Arnold


Ed Shaya wrote:
> ...
> I don't understand why there are so many TopConcepts, most of which have 
>   many layers of broader things above it.
> For instance _21_cm_line is a top concept, yet broader is 
> radio_recombination_lines, broader is recombination_lines, broader is 
> emission_lines, broader is specral_lines.  I would perhaps accept 
> spectral_lines as a TopConcept.
> 
> ...
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Arnold H. Rots                                Chandra X-ray Science Center
Smithsonian Astrophysical Observatory                tel:  +1 617 496 7701
60 Garden Street, MS 67                              fax:  +1 617 495 7356
Cambridge, MA 02138                             arots at head.cfa.harvard.edu
USA                                     http://hea-www.harvard.edu/~arots/
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