In message , Steve Willner
writes
The nitrogen-15 carriers in IDPs have not been securely identified but are
possibly organic macromolecules or polycyclic aromatic hydrocarbons (PAHs).
It is thus possible that the additional parent(s) of cometary CN may belong
to this ensemble of organic substances.

In article ,
Jonathan Silverlight writes:
I can't help feeling that Chandra Wickramasinghe is going to like that
observation.

I don't see why. PAH's are widely accepted as dust constituents
these days, and there is no indication they are biological. Quite
the contrary, I should think. Their structure is multiple "benzene
rings." (Visualize those small hexagonal bathroom tiles.) Are such
structures known in biology?

That was my point! Hoyle and Wickramasinghe claimed that the spectra
they recorded were biogenic, rather than just organic, for instance. And
the nitrogen-containing macromolecules _are_ suggestive of "interesting"
molecules.
But thinking about hexagonal tiles reminds me of something scary.
Remember the structure of the Andromeda Strain? ;-)
--
"Forty millions of miles it was from us, more than forty millions of miles of
void"