What causes the striking red color associated with some parts of many emission nebulae?

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    electrons in hydrogen atoms making transitions from their n = 3 to n = 2 atomic states
     absorption of starlight in the dust of the interstellar medium
     molecular hydrogen undergoing a rotational transition from a higher to a lower energy state
     doubly ionized oxygen undergoing a rare "forbidden" electronic transition
     electrons in individual hydrogen atoms flipping their intrinsic spin states from being parallel to being antiparallel to that of their parent protons
asked Sep 20, 2012 in Astronomy by anonymous
    

1 Answer

0 votes
electrons in hydrogen atoms making transitions from their n = 3 to n = 2 atomic states
answered Sep 22, 2012 by SkyStar ~Expert~ (2,855 points)



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