Desktop Project Part 21: Dancing in the dark filaments

By Phil Plait | April 15, 2012 7:00 am

[My Desktop Project — clearing off the cool astropix from my computer’s desktop by posting one each day — is getting close to being done soon; I’m down to my last few pictures!]

It’s funny how different the Sun looks at different wavelengths of light. In visible light, you can see all sorts of surface features like sunspots, granules (rising and falling packets of gas convecting like a pot of water on a stovetop), and more.

But when you have eyes sensitive to the ultraviolet, the Sun takes on an entirely new appearance. That’s where the effects of the Sun’s active and crazy magnetic field claim dominion, and you see vast arcs, loops, and towers of incredibly hot plasma. To be fair, you can see this in visible light too, but it’s not quite so… dynamic. Cue NASA’s Solar Dynamics Observatory, and its UV detectors:

This image was taken by SDO on March 28, 2012, and shows the limb of the Sun at a wavelength of 19.3 nanometers — well into the UV. What you’re seeing is plasma — gas so energetic it’s had electrons ripped right off its atoms, putting it under the sway of the Sun’s fierce magnetism. The plasma flows along the magnetic field lines, arcing high off the surface into space before coming back down.

Usually, those arcs are hot and bright, like the tight loops you can see on the left (within hours, those loops got bigger and brighter, making dozens of well-defined glowing coils). But you can also see a dark arc in the center, going from just below the center of this picture, curving to the upper left, then heading up and over to the right, off the face of the Sun. For some reason, the plasma there wasn’t quite as hot, and so instead of glowing at this wavelength it appears dark, absorbing the light from material behind it.

I took this shot using Helioviewer.org — if you click the picture it will take you there. You can then play with the controls on the left and watch this dark filament change, grow, dance, and playfully flow from one arc base to the other. It’s mesmerizing. SDO has a page with some pre-made animations, too.

I love how we see the Sun pretty much every day, but in many ways it is as unfamiliar as any distant star. Happily, though, our drive to explore and understand has led us to the point where we can investigate our nearest star, and learn more about it. Given that it’s the main driver of life on Earth, this is probably a smart idea.

Image credit: NASA/SDO/Helioviewer.org


Related Posts:

Desktop Project Part 8: From filament to prominence
The Sun’s angry red spot
HUGE sunspots turning toward Earth
The comet and the Coronal Mass Ejection

CATEGORIZED UNDER: Astronomy, Pretty pictures

Comments (6)

  1. Messier Tidy Upper

    It’s funny how different the Sun looks at different wavelengths of light. In visible light, you can see all sorts of surface features like sunspots, granules (rising and falling packets of gas convecting like a pot of water on a stovetop), and more.

    There’s nothing quite like seeing our Daytime Star rendered vivid crimson by a hydrogen-alpha filter! ;-)

    A remarkable sight I’d recommend to all.
    And when you realise the scale of a sunspot or solar prominence,
    Yegods! How it makes our Earth look small! 8)

    Great image with the ultra-violent turned amber yellow and black, not true colour but a truer picture than meager human eyes could see. :-)

    PS. Earth to scale here woud be how big?

  2. Infinite123Lifer

    “I’m down to my last few pictures!”

    I hope thats a cue. :'(

  3. Thopter

    “What you’re seeing is plasma — gas so energetic it’s had electrons ripped right off its atoms, putting it under the sway of the Sun’s fierce magnetism.”

    Since the Sun is mostly hydrogen, does that then mean that we’re looking at a big boiling pot of proton soup?

  4. Wzrd1

    Even more impressive is the sun in x-ray, where one sees the most energetic events, such as magnetic reconnection.

  5. Nigel Depledge

    This is super-cool. Or, well, y’know, hot.

    . . . shows the limb of the Sun at a wavelength of 19.3 nanometers . . .

    Thank-you so much for using SI units here.

  6. Luke Miller

    The UV imagery is stunning. I’ve seen photo before but the movie clip is phenomenal (http://sdo.gsfc.nasa.gov/gallery/potw.php?v=item&id=94 ). The exchange between two magnetic coils (?) is so dynamic and ethereal.

    But now the other half of my brain interjects: We are seeing gas flowing between the fields right? So this could be considered wind? Then how fast it is going? The movie description has 450 frames x 3 minutes = 22.5 hrs, but what is the scale of the image? How far apart are the two poles and how tall are they?

    And by the way. Where the heck are the hi-res versions? I tried to put this on my laptops wallpaper and it looks like junk. Is this limited by the resolution of the optics floating around up there or by the .gov sites not sharing links to their hi-res folders?

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