B What Are the Linear Dark Features on the Sun?

  • B
  • Thread starter Thread starter mollwollfumble
  • Start date Start date
  • Tags Tags
    Linear Sun The sun
AI Thread Summary
The discussion centers on identifying long linear dark features observed on the Sun, which are suggested to be coronal holes or possibly filaments and spicules. These features often have a jagged light line along their center and can obscure solar flares and spicules. Participants debate whether these dark lines are indeed solar flares, with some noting that flares would typically appear bright rather than dark. The conversation highlights the challenges of visualizing these features in different wavelengths, particularly X-ray versus hydrogen alpha images. Overall, the scientific community is still exploring the exact nature of these enigmatic solar phenomena.
mollwollfumble
Messages
34
Reaction score
5
TL;DR Summary
What are the long linear dark features on the Sun, with a thin light jagged centreline and dark spikes above?
I’ve been watching
https://www.youtube.com/watch?v=l3QQQu7QLoM
What is the scientific name of the enigmatic long linear dark features? I’ve marked five of them in the first image, from time 7:55 in the video.

Each linear dark feature usually (but not always) has a thin jagged light line along the centreline. At the limb of the Sun, each jagged centreline appears as a dark spike that protrudes well above the surroundings and is so dark that it obscures flares and spicules behind it. The second image from 0:33 shows three such dark spikes, two on the left and one on the right, which are always aligned with the thin centreline of a dark feature.

If you think of the dark spikes above the thin jagged centreline as cloud tops, then there is often lightning that plays along these cloud tops. These are flashes of light along this very thin central line. It can be faint and almost continuous, localised, can zoom from one end of the line to the other like a speeding car on the highway, or go bang all at once. These flashes are not high above the photosphere like flares, but seem contained within the cloud tops.

Anyway, what is the scientific name for these?
 

Attachments

  • Sun canyon1.jpg
    Sun canyon1.jpg
    57.4 KB · Views: 306
  • Sun canyon2.jpg
    Sun canyon2.jpg
    14.9 KB · Views: 333
  • Like
Likes hutchphd
Astronomy news on Phys.org
Last edited:
  • Like
Likes phinds
Andrew Mason said:
I think you may be referring to solar flares. Seen from above rather than the side flares can look like dark lines as in these Wikipedia photos: https://en.m.wikipedia.org/wiki/Solar_flare

AM

I don't see any obvious flares in in any of the boxed regions. and the flares would be bright not dark

mollwollfumble said:
What is the scientific name of the enigmatic long linear dark features? I’ve marked five of them in the first image, from time 7:55 in the video

in the first pic ...

1593939683014.png


These long dark areas are gaps in the corona called coronal holes. Some of them may also be some face on filaments there as well
tho that X-ray wavelength doesn't show filaments so well compared to Ha (hydrogen Alpha) images.

Now the second image shows a different feature...

1593939880956.png


The left box outlines a very small filament/prominence ( also not well seen at these wavelengths)
These could also be spicules - small plasma jets as they look similar to small prominences when viewed side on

The right box may also be one, but much less defined
cheers
Dave
 
mollwollfumble said:
I’ve been watching

What a great video...a complete solar cycle in an hour. Thanks. (I don't know the answer...)
 
  • Like
Likes sophiecentaur
This thread is dedicated to the beauty and awesomeness of our Universe. If you feel like it, please share video clips and photos (or nice animations) of space and objects in space in this thread. Your posts, clips and photos may by all means include scientific information; that does not make it less beautiful to me (n.b. the posts must of course comply with the PF guidelines, i.e. regarding science, only mainstream science is allowed, fringe/pseudoscience is not allowed). n.b. I start this...
Today at about 4:30 am I saw the conjunction of Venus and Jupiter, where they were about the width of the full moon, or one half degree apart. Did anyone else see it? Edit: The moon is 2,200 miles in diameter and at a distance of 240,000 miles. Thereby it subtends an angle in radians of 2,200/240,000=.01 (approximately). With pi radians being 180 degrees, one radian is 57.3 degrees, so that .01 radians is about .50 degrees (angle subtended by the moon). (.57 to be more exact, but with...
Back
Top