What Are the Linear Dark Features on the Sun?

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Discussion Overview

The discussion revolves around the identification of long linear dark features observed on the Sun, as depicted in a video. Participants explore potential scientific names and explanations for these features, considering various solar phenomena.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant describes the features as linear dark spikes with a jagged light line along the center, suggesting they may resemble cloud tops with flashes of light.
  • Another participant proposes that these features could be solar flares, referencing images that depict flares as dark lines when viewed from above.
  • A different participant challenges the flare hypothesis, noting that flares would typically appear bright rather than dark and suggests that the features might be coronal holes or filaments.
  • This participant also mentions the possibility of small plasma jets, known as spicules, being present in the observed images.
  • Several participants express appreciation for the video showcasing a complete solar cycle, although they do not provide definitive answers to the original question.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the identification of the dark features. Multiple competing views are presented, including the possibility of solar flares, coronal holes, filaments, and spicules.

Contextual Notes

There are limitations in the discussion regarding the visibility of certain features at specific wavelengths, as well as the dependence on the perspective from which the solar phenomena are observed.

mollwollfumble
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TL;DR
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?
 

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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...)
 
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