The Sun lets out a brief flare

By Phil Plait | July 30, 2011 11:25 am

Around 02:00 UTC last night (July 30, 2011), a sunspot named Active Region 1261 erupted with a short solar flare, which was caught by NASA’s Solar Dynamics Observatory. Using Helioviewer I created a short video of the event:

[Make sure to set the resolution to at least 720p!]

Those bright regions are actually sunspots, which are dark at wavelengths our eyes can see, but are quite bright in the ultraviolet. Solar flares occur when the Sun’s magnetic field lines get twisted up. They store a lot of energy, and when tangled they can suddenly snap, releasing that energy. Astronomers classify flares by the energy released in X-rays, from Classes A,B, and C (weak) to M (moderate) to X (yikes!). This one was an M9, which is on the low high end of the M class. Powerful, but probably not enough to affect us here 150 million kilometers away. If anything, there may be a stronger than normal aurora in a day or two.

The Sun’s activity waxes and wanes on a roughly 11 year cycle, and we’re on the upswing of Cycle 24. There was an unusually long quiet period after Cycle 23 and the start of this one, and the new cycle has been slow to rise. It’s not clear what this means, although there is some evidence this cycle may be weak. I am agnostic on this; the evidence is interesting but not conclusive. The Sun is fiercely complex, and its magnetic field even more so. The best thing we can do is continue to watch it and see what happens, and use that information to better our understanding of this nearest star to Earth.

Credit: NASA/SDO/Helioviewer. Tip o’ the welder’s goggles to Little SDO on Facebook.


Related posts:

- Incredible solar flare video
- kaBLAM! Footage of the X-class solar flare
- Followup: Sunspot group’s loopy magnetism
- The Sun may be headed for a little quiet time
- A fiery angel erupts from the Sun

CATEGORIZED UNDER: Astronomy, Pretty pictures
MORE ABOUT: SDO, solar flare, Sun

Comments (11)

  1. Sam H

    I can see the spot marginally brightening about half a second after the flare – billions of tons of falling ejected plasma reenergizing the surface magnetic fields or something?

  2. I didn’t see much in the second version.

  3. I love these videos. Thanks for posting them.
    Is the long ‘vertical’ streak at 13 sec. the equivalent of camera glare, or is the energy release traveling in that straight a line?

  4. Messier Tidy Upper

    An M9 flare BA? That sounds like something that a red dwarf or red giant star would put out rather than a yellow dwarf like our daytime star! Given our Sun’s spectral classification shouldn’t that be a G2 flare? ;-)

    (Yeah, I know, flare classes don’t equal spectral ones.)

    Neat video thanks but you can’t afford to blink. 8)

  5. DrFlimmer

    @ #4 Margaret K. Westfall

    The vertical streak is due to too much radiation causing the pixel(s) to overflow. It’s an artifact of the detection system and not a real thing. The explosion was just too bright.

  6. jearley

    We are monitoring that area here at the NSO. Pretty interesting magnetic field orientation, from what I was told Friday, and it was easy to see heightened CaII activity in the scans that I took yesterday. The Sun is looking more active right now than in any time that I have seen it this year. Three nice sunspot groups, and maybe another forming.

  7. Patrick

    Bad Astronomy blog, I would like to point out that your astronomy is bad. LOL An M9 solar flare is actually the highest M class flare, just slightly weaker than an X Class Flare. You can see the X-Ray Flux here….
    http://www.sec.noaa.gov/rt_plots/Xray.gif

  8. Patirck (8): You’re right! I fixed the text. The problem with the visual magnitude system is it gets me thinking backwards. :)

  9. Joseph

    When are the cycles measured from? If this is the beginning of cycle 24 did we (humans) begin recording cycles in the 1740′s? I know we have been observing the skies for far longer then that.

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