by MarkBour » Mon Jun 18, 2018 4:00 pm
When I watch a prominence form and flow in a video such as this, it looks a lot like fluid material is making up exactly the portion that we see. In still photographs I used to see, I had no reason to doubt this: a vast arc of bright orange looked like some of the gas at the Sun's surface was following a bridged path, having jumped out of the Sun and arced outward until gravity pulled it back down. Prominences often had roughly the parabolic shapes of a ballistic trajectory.
I now think this is a poor description of the overall movement, which is more like a rope that has been "thrown away" from the surface ()perhaps there is a better term). Also, as I watch videos of prominences, it appears that we are only seeing part of the material flow visibly. I conclude that some of the material ejected with a prominence is unseen (to my eyes), but it may show itself as the display progresses, changing from unseen to light-emitting. Clearly, some of that material is giving off radiation/light above the amount of radiation from the corona. Whereas some things I have read talk about photons being generated deep in the Sun and working their way out to the surface, clearly the material itself in a prominence is giving off light, and some parts of it are much brighter than others.
What makes some material in a prominence visible to us? And within that, what causes some parts of a visible prominence to radiate a lot more light than the rest? Is this hydrogen gas giving off blackbody radiation? Are the brighter parts being energized from the magnetic field? Is there a bit of fusion happening way out in the middle of a prominence? Or are the visibly brighter parts actually only bright in the visible part of the spectrum -- perhaps they are less energetic than other parts of the prominence, which might be radiating at higher frequencies than I can see.
When I watch a prominence form and flow in a video such as this, it looks a lot like [b]fluid material [/b] is making up exactly the portion that we see. In still photographs I used to see, I had no reason to doubt this: a vast arc of bright orange looked like some of the gas at the Sun's surface was following a bridged path, having jumped out of the Sun and arced outward until gravity pulled it back down. Prominences often had roughly the parabolic shapes of a ballistic trajectory.
I now think this is a poor description of the overall movement, which is more like a rope that has been "thrown away" from the surface ()perhaps there is a better term). Also, as I watch videos of prominences, it appears that we are only seeing part of the material flow visibly. I conclude that some of the material ejected with a prominence is unseen (to my eyes), but it may show itself as the display progresses, changing from unseen to light-emitting. Clearly, some of that material is giving off radiation/light above the amount of radiation from the corona. Whereas some things I have read talk about photons being generated deep in the Sun and working their way out to the surface, clearly the material itself in a prominence is giving off light, and some parts of it are much brighter than others.
What makes some material in a prominence visible to us? And within that, what causes some parts of a visible prominence to radiate a lot more light than the rest? Is this hydrogen gas giving off blackbody radiation? Are the brighter parts being energized from the magnetic field? Is there a bit of fusion happening way out in the middle of a prominence? Or are the [i]visibly[/i] brighter parts actually only bright in the visible part of the spectrum -- perhaps they are [i]less[/i] energetic than other parts of the prominence, which might be radiating at higher frequencies than I can see.