by DavidLeodis » Wed Apr 09, 2014 11:12 am
In the information brought up through the first link in the explanation to this APOD it states "Observers have long noted a distinctive greenish tint to the nebula, in addition to regions of red and of blue-violet...The green hue was a puzzle for astronomers in the early part of the 20th century because none of the known spectral lines at that time could explain it. There was some speculation that the lines were caused by a new element, and the name "nebulium" was coined for this mysterious material. With better understanding of atomic physics, however, it was later determined that the green spectrum was caused by a low-probability electron transition in doubly ionized oxygen, a so-called "forbidden transition". This radiation was all but impossible to reproduce in the laboratory because it depended on the quiescent and nearly collision-free environment found in deep space.".
Wow! nebulium, mysterious material, low-probability electron transition, forbidden transition, etc. All fascinating stuff.
One personal gripe (apart from the colours of the processed image) is that as I like to use links in the explanation to APODs I did find the
27 links in the explanation to this APOD were far too many, such that I gave up on using many of them. There has been a tendency for quite some time now to increase the number of links to further information (which must take time in the production of an APOD) but I wonder just how many ever get used?
In the information brought up through the first link in the explanation to this APOD it states "Observers have long noted a distinctive greenish tint to the nebula, in addition to regions of red and of blue-violet...The green hue was a puzzle for astronomers in the early part of the 20th century because none of the known spectral lines at that time could explain it. There was some speculation that the lines were caused by a new element, and the name "nebulium" was coined for this mysterious material. With better understanding of atomic physics, however, it was later determined that the green spectrum was caused by a low-probability electron transition in doubly ionized oxygen, a so-called "forbidden transition". This radiation was all but impossible to reproduce in the laboratory because it depended on the quiescent and nearly collision-free environment found in deep space.".
Wow! nebulium, mysterious material, low-probability electron transition, forbidden transition, etc. All fascinating stuff. :)
One personal gripe (apart from the colours of the processed image) is that as I like to use links in the explanation to APODs I did find the [u]27 links[/u] in the explanation to this APOD were far too many, such that I gave up on using many of them. There has been a tendency for quite some time now to increase the number of links to further information (which must take time in the production of an APOD) but I wonder just how many ever get used?