I ame always awestruck watching films (false-colored, I guess) of the sun going about its life.
The subject/header question. I learned the terms from this page. (It’s a continuous blog, so the diagram is in the middle somewhere.)
You can actually see–not so much in this clip–where the jets of flame “splash” when they re-land on the surface. What is going on there?
Why is the surface so granular as it looks it’s “boiling”?
Thanks,
Leo
The Sun always has a corona, that just being everything of the Sun that’s above the photosphere (the bright part we usually see). A prominence is one sort of feature that can occur in the corona, where a loop of hot plasma along a magnetic field line extends above the photosphere and glows brighter than the rest of the corona.
Things that look like splashes are, basically, splashes. But they’re a lot more complicated than splashes in water, because the dynamics of both the fluid and the magnetic fields are significant, and are intertwined in a complicated way.
And the granularity of the surface is indeed due to something akin to boiling. One of the major ways heat is transported from the interior of the Sun to the surface is via convection: Hot blobs of plasma are less dense and rise due to buoyancy, while cold blobs are more dense and sink. But the hot and cold blobs can’t just pass right through each other, so what ends up happening is that you get a pattern on the surface where hot material is rising in some spots, while cold material is sinking in other spots. Each one of those grains you see has hot stuff rising in the center, and cold stuff sinking around the edges. A similar process occurs in a pot of boiling water, which is why it looks like boiling.
The corona is very diffuse high-temperature plasma, usually above 1 million degrees (K). A prominence is a structure made of cooler plasma (maybe tens of thousands of degrees) that projects into the corona, supported by magnetic fields.
I’m not sure about the “splashes” - are you talking about this video?
The Corona is the “halo” effect caused by the brightness in the sky (question?), whereas the bubbling mass is what the Sun is: A Ginormous Bubbling Mass of Magma and Fire.
Technically, when solar physicists talk about the “corona” we’re specifically referring to the very hot plasma at millions of degrees, and not including the chromosphere (which lies just above the photosphere and at tens of thousands of degrees) or the transition region (i.e. transition from chromosphere to corona). And also not including the solar wind, which is above/beyond the corona.
Valid nitpick about the chromosphere and transition region, but many folks consider the solar wind (if they consider it at all) to be technically part of the corona. There’s not really a sharp distinction between them.
NO. Almost nothing you wrote is correct.
The Sun has no magma & no fire.
Although it is ginormous and does something kinda like bubbling on time- & distance- scales laymen find hard to comprehend.
The corona is a component of the Sun itself & has nothing whatever to do with the bloom of surrounding brightness you believe you see in our atmosphere. That’s a mix of atmospheric diffraction and a physiological reaction in your eye to oversaturation with excess light.
This vid just came over the transom. It is a succession of overlaid images of the photosphere “downwards,” culminating in lines of magnetic fields.
I sort of lost understanding of the thread. Can anyone comment on the images? Of course, they are endlessly fascinating.
It’s not going “down”, it’s going “up”. The first image, in visible light (and the only one in anything resembling true color) is of the photosphere. That’s the lowest layer we can see directly; it’s opaque, so we can’t see anything lower. The later images are in the extreme UV or X-ray range, where you only see things if they’re extremely hot. For reasons that aren’t entirely understood, the corona of the Sun is much hotter than the photosphere, so it shows up in these hot wavelength bands. The final image, with the added magnetic field lines, isn’t an observation, but an extrapolation from the observations using some sort of computer model. You’ll note that the loopy structures in the corona seem to correspond to the loops of the magnetic field. SDO (the satellite that took these pictures) also collects a number of other sorts of data which were used to make those models (in particular, the magnetogram, which measures the strength of the line-of-sight component of the magnetic field, is very important), but those don’t look as pretty, so they didn’t make it into the YouTube video.