Which of the following mechanisms is responsible for creation of the 21-cm radio line used by astronomers to study interstellar gas?

0 votes
    Doubly ionized oxygen undergoes a rare "forbidden" electronic transition.
     Electrons in individual hydrogen atoms flip their intrinsic spin states from being parallel to being antiparallel to that of their parent protons.
     Molecular hydrogen undergoes a rotational transition from a higher to a lower energy state.
     Electrons in the first excited state of atomic hydrogen make a transition to the ground state.
     All of the mechanisms listed here can produce 21-cm emission.
asked Sep 20, 2012 in Astronomy by anonymous
    

1 Answer

0 votes
Electrons in individual hydrogen atoms flip their intrinsic spin states from being parallel to being antiparallel to that of their parent protons.
answered Sep 22, 2012 by SkyStar ~Expert~ (2,855 points)



...