i'd appreciate it if anyone could offer up any interesting findings they might have come across when researching forbidden lines in relation to neutral hydrogen. Thank you much. I look forward to any insight into this topic beyond what Wiki(and it's ilk) offers.

Are you looking for anything in particular?

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just anything in particular that interested you regarding the relationship of oen to the other.

AND any interesting links you found to any other astronomical/physics subject.

I'm interested in learning of the points on this subject that intrigued others in the forums :-)

Hmmm, aside from the idea that they were forbidden historically, but are actually common in space was interesting to me, but that was it. Do you think there's more to it than that?

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try this page: http://www.daviddarling.info/encyclo...dden_line.html

thanks much :-)

There is a bit more too it:
I'm researching its relevance given the recent findings on the structure of the neutron(and the proton/quark-based particles for that matter).

I am referencing the subject highlighted in the following article(and others):
http://www.physorg.com/news109259529.html

the differences between the classical model of the hadron, and this model piqued my interest again with relation to the interactions of neutral hydrogen/interstellar medium/forbidden lines...

Thanks a ton, I appreciate your input.

Metastable states are systems that have a precarious stability that can be easily disturbed. Just a slight disturbance will cause the system in a metastable state to fall to a lower energy level. A spinning top or a pencil standing on its lead point are examples.

"Forbidden" lines just refers to the improbabilty of viewing transitions through a spectroscope but if that spectroscope can read radio frequencies it can pick up the 21 cm line caused by neutral hydrogen when it is temporarily disturbed by a collision, causing its associated electron to flip to the metastable state and then return.

http://www.infoplease.com/ce6/sci/A0858876.html

Neutral hydrogen is also seen with X-ray telescopes placed outside of our atmosphere. It is seen at any center of mass of a galaxy cluster where large amounts of neutral hydrogen will gravitate in quite large masses, often 3 to 4 times as massive as all the stars of the galaxies in their associated clusters. They will glow in the X-ray region of the spectrum. The amount the X-ray density changes over a given angular area can be crunched mathematically to calculate the mass.

Those same locations (galaxy cluster center of masses) reveal that same neutral hydrogen independently in the CMB where CMB photons were scattered by those neutral hydrogen collisions. They show up as spots in the CMB. The interference pattern of the CMB upon itself and the sizes of the spots can be calculated to give the same results concerning mass amounts that are in agreement with the X-ray telescopic calculations mentioned above.

with relation to the theme of this thread: any thoughts on possible ramifications of the recent findings on a neutron's electrical charge, and its quark-based structure.

http://www.physorg.com/news109259529.html
a link to reference my post, just in case

I don't know how neutral hydrogen would have anything to do with the structure and magnetic properties of the neutron and its associated quarks and charge distribution. That link you provided likely will make some of us think of tying that to a neutron star's magnetic field behavior or how experiments concerning the virtual strange sea may also tie in and influence the magnetic properties of a neutron.

exactly one of the thoughts on my mind, sea/valence influence...
hmm