by JohnD » Thu Oct 27, 2016 7:51 am
Bit of a thread diversion,but "the telltale blue-green emission from doubly ionized oxygen atoms" raises a long held Q, about aurorae.
How is it that one element becomes ionised, or doubly ionised, in a mixture of several other gases>
The aurora shows distinct green or red displays, said to be oxygen and nitrogen respectively, when the mixture of gases at that height is the same as at ground level, with no layering, certainly not in the apparently vertical "curtains" that the aurora shows.
In this APOD, a highly discrete area glows with an oxygen discharge - it seems unlikely that a cosmic gas cloud should have a bubble of oxygen in it, conveniently close to a solurce of radiation.
So how is a specific element energised, in the aurora or the Squid?
JOhn
Bit of a thread diversion,but "the telltale blue-green emission from doubly ionized oxygen atoms" raises a long held Q, about aurorae.
How is it that one element becomes ionised, or doubly ionised, in a mixture of several other gases>
The aurora shows distinct green or red displays, said to be oxygen and nitrogen respectively, when the mixture of gases at that height is the same as at ground level, with no layering, certainly not in the apparently vertical "curtains" that the aurora shows.
In this APOD, a highly discrete area glows with an oxygen discharge - it seems unlikely that a cosmic gas cloud should have a bubble of oxygen in it, conveniently close to a solurce of radiation.
So how is a specific element energised, in the aurora or the Squid?
JOhn