Followup: Sunspot group's loopy magnetism

By Phil Plait | April 20, 2011 7:00 am

Yesterday I posted a video showing a cluster of sunspots forming on the Sun’s surface. As it happens, a new video was released last night from NASA’s Solar Dynamics Observatory satellite showing this same sunspot group, but this time, along with the visible light images, we also get X-ray images. X-rays are emitted by plasma trapped in magnetic fields, so in a sense you can actually see the magnetism of the sunspots as they evolve. Watch!

How awesome is that? The full disk picture on the left combines visible and X-ray light, the lower right shows the spots in just visible light, and the upper right is just X-rays. You can see the magnetic field lines looping from one part of the sunspot cluster to another as the plasma follows them. If you look carefully, you’ll see flashes of brightness, too: those are solar flares!

The magnetic field stores energy. If the loops get tangled together, they can snap and release their energy in one sudden burst (like a box full of mousetraps, if you happened to see my episode of "Bad Universe" on Discovery Channel yesterday). What’s interesting about this video is that it shows that the rotation of the sunspots plays into this too.

Imagine a bunch of magnetic field lines coming from a spot, going up above the Sun’s surface, then back down to another spot. If the spot is rotating, that cluster of loops will get twisted up, just like a rubber band gets twisted when you rotate one end (do you kids these days still play with balsa wood airplanes that use a rubber band to spin the propeller? It’s just like that).

If the loops get too twisted, they’ll snap, too, and kablam! Solar flare. Remember, this was the biggest flare seen in several years, so apparently having several rotating spots feeding into the system really pumps a lot of energy into the loops. That makes sense, and it means that clusters of spots may be the ones we should keep our eyes on if we want to catch big flares in the act.

Video credit: Movie produced by D. Brown (UCLan). Data courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.

Related posts:

The birth of a sunspot cluster
Incredible solar flare video
Sunlight and a spot of calcium
One solar piece of flare


Comments (8)

  1. do you kids these days still play with balsa wood airplanes that use a rubber band to spin the propeller? It’s just like that

    I did. And I made them explode on more than one occasion. My own balsa wood flare. :)

    EDIT: Oops, had the wrong thing in my clipboard….


    Phil Plait:

    [D]o you kids these days still play with balsa wood airplanes that use a rubber band to spin the propeller?

    These days, the bloody spoiled brats are not interested if it doesn’t run on batteries and doesn’t have full remote control!

  3. John Baxter

    Dear Virgin Space Cruises,
    Please cancel my reservation for the Mercury / Sun cruise. Too violent.

  4. jearley

    Actually, I was just talking with my classes about sunspots, using the same analogy about balsa wood planes, and kids DO still play with them, and still have the rubber bands snap. Cultural continuity!

  5. Messier Tidy Upper

    @ 3. John Baxter :

    Dear Virgin space cruises – I’m happy to take any cancelled seat for that Sun/Mercury cruise you’ve got going! 😉

    Nice videoclip there but so much going on I had to watch it quite a few times. Not that that presented any hardship or problem. :-)

  6. The lower right inset video resembles mandelbrot sets (or julia sets?) in motion. Pretty spectacular.

  7. daniel mayberry

    wonder if some of the same concepts with magnetic fields and combustible energy could be used in an engine? Not like that has never been thought of huh?


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