Awesome X2-class solar flare caught by SDO

By Phil Plait | September 26, 2011 6:00 am

On Saturday, September 24, 2011, at 09:40 UT, most of the folks working for NASA were probably asleep. But NASA’s Solar Dynamic Observatory never sleeps: it’s only job is to stare at the Sun, 24 hours a day, every day.

Good thing it does, too, because it caught a pretty decent-sized solar flare erupting from the Sun’s disk at that time:

Isn’t that awesome? Make sure you set the resolution to at least 720p and make it full screen for the full effect.

The flare was technically class X1.9, which is at the low end of the highest category of flare power. It blasted out radiation across the electromagnetic spectrum (this animation shows the Sun in the far-ultraviolet), and probably released at least as much energy as a billion one-megaton bombs.

Good thing we’re 150 million kilometers away. Yegads.

The flickering threw me for a sec, but if you pause the video during the flare, you’ll see it’s due to the flare changing its brightness. The software used to create the animation automatically accounts for total brightness in an image, so when the flare gets bright the overall image brightness gets turned down. The brightness varied pretty rapidly, changing on a time scale of just a few minutes; since the animation is sped up we see it flickering. The entire flaring episode lasts just less than an hour.

The X-shape, streaks, and vertical line you see during the flare are instrument artifacts and aren’t real. They’re like the cross-shaped diffraction spikes you see in bright star images with Hubble.

The flare came from a sunspot cluster called Active Region 1302; "amateur" astronomer Alan Friedman got a fantastic shot of them just the other day, seen here (click to ensolarnate).

There are vast energies stored in the magnetic field lines piercing those spots. Those lines get tangled up, and can suddenly snap, releasing that energy as an intense burst of light as well as a blast of subatomic particles (for details on this, read this earlier post on how sunspots make solar flares).

That region is pretty feisty, and the odds of us getting more flares from those spots are pretty good. The Sun’s rotation is currently taking them toward the center of the disk, where a good sized explosion is then directed toward us, and particle waves from the blast can then interact more efficiently with our magnetic field. We may be getting aurorae from them, and if things go well that’s all we’ll get! A big blast can damage satellites, and even put astronauts on the ISS at risk. We on the ground are pretty safe, since the Earth’s air absorbs the radiation — that’s why we have to launch satellites like SDO into space, so they can detect that energy in the first place!

However, a big blast can shake the Earth’s magnetic field, inducing a current in the ground that can actually overload power lines. We can get blackouts from such things, and it’s happened before. This is a real problem that can do millions or even billions of dollars of infrastructure damage (including money in the economy lost during the blackout). I know a lot of solar physicists are concerned about this eventuality, and are trying to get both the power companies and the government to take it seriously. I hope they do. We’re still approaching the peak of the solar cycle sometime in mid-2013 or so, and flares like the one Saturday will most likely be more common.

Credits: NASA/SDO; Alan Friedman

Related posts:

First earthward-heading solar flare of the cycle
Solar storm tracked all the way from the Sun to Earth
Another big solar flare
Scientists see sunspots forming 60,000 km below the Sun’s surface!

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

Comments (21)

  1. Wait a minute. If the NASA folks were asleep, then it must have been night. The Sun doesn’t shine at night, so how could there have been a solar flare? This is an obvious hoax. You can’t fool me, Phil.

  2. Lorena

    hi, phil, on a totally unrelated topic, there was an explosion in a house in argentina today, in a very humble neighborhood, and some people are talking about “a red fire ball that light up the sky” and that the sound was that of a bomb and it was heard in 10kms . The fire men said they didnt see anything, and they thought of a gas explosion, but the causes are still unkwnown. people are talking about space debris or a meteorite. one dead and 6 injured because of that. this is the picture of the ball: take care.

  3. Dr. Plait, (re last paragraph) doesn’t the risk of damage to the powergrid depend on the polarity of the charged particles hitting the earth? I thought I remember reading that a while back, and that may be a factor in the inattentiveness of government/power companies. They just think it won’t happen because of that.

  4. RwFlynn

    It’s times like these when I wish my dinosaur could handle a full 1080 resolution. Alas, for I will have to make do with 720 pixels.
    /first world problems

  5. omatranter

    So that whats been causing global warming for or these years, how many years I don’t know, I don’t think anybody knows, in Texas we teach that Global warming is both a con but that the next Ice Age can only be stopped by burning lots of oil and coal to get those greenhouse gases up to warm the planet, we don’t take sides :)

  6. fco.

    There was a big blackout here in Chile that same day. I wonder if it had something to do with this.

  7. @ 3. Larian LeQuella :

    Dr. Plait, (re last paragraph) doesn’t the risk of damage to the powergrid depend on the polarity of the charged particles hitting the earth? I thought I remember reading that a while back, and that may be a factor in the inattentiveness of government/power companies. They just think it won’t happen because of that.

    Or, maybe, because some Doctor there knows how to reverse the polarity of the neutron flow? 😉

    Strange video – a blue Sun strobing us like an unstable Mirzam* (Beta Canis Majoris) variable.

    Someone needs to tweak the clip so that after the rapid flickering there’s a pop and it goes out leaving everything on Earth pitch black! 😉


    * Click on my name for info. on Mirzam via Kaler’s Stars website. Mirzam / Beta Canis Majoris variables are Also Known As Beta Cephei variables which is rather ufair given the whole Cepheid variable class potential confusion. Quit hogging the variable classes Cepheus! 😉

    PS. Mirzam – like our Sun – is a “constant variable” with its subtle pulsations and flickering visible only to scientific instruments and not to the unaided human eye.

  8. sophia8

    Here’s the one news article I could find about that Argentina explosion:
    The picture linked in Lorena’s post looks like an arcing piece of flaming debris; it could possibly be the gas canister that caused the explosion. If the image is genuine, the ‘fireball’ looks way too square and regular to be something from space.

  9. Skeptic

    @ Lorena.. Maybe it was a piece of satellite that crashed!? 😛 however I strongly doubt it

  10. @5. omatranter :

    I take it that you’re joking there – but sadly many folks do believe our daytime star is the cause of the HIRGO* problem.

    Before any climate contrarians pop up here and make that long debunked claim please watch :

    plus this more recent youtube clip esp. focusing on the cosmic rays idea :

    & read :

    which shows that whilst the Earth has been getting hotter – our Sun has been in a cooling phase and if anything should be making us colder and thus could even be hiding the true scale of the problem from us. :-(


    * Human Induced Rapid Global Overheating – a better, clearer, more accurately description than Anthropogenic Global Warming in my view. Please pass this meme along!

    PS. Latest Climate crock video is linked to my name. New one just out. :-)

  11. Chris

    If you live north, you might be lucky and see some auroras tonight from the flare. Unfortunately it’s cloudy and rainy here so I’ll have to wait.

  12. Calli Arcale

    Chris — likewise, I have come to the belief (because correlation equals causation, natch) that aurorae, meteor showers, interesting satellite passes, and similar events trigger rainfall. 😀

  13. Wzrd1

    Calli, I’ve long ago arrived at the firm conclusion that rainy weather is a REQUIREMENT for any celestial phenomena to occur in my area. :/

    Messier, as I recall, precession has more to do with environmental heating/cooling than simple solar forcing. That said, we ARE getting slightly more heat delivered, secondary to sunspot activity.
    Meanwhile, we continue to pump massive amounts of greenhouse gases into the atmosphere and pretend it won’t have an impact, while griping about droughts, fires, extreme weather events and disasters…

  14. Fatima M.

    Well we just had a blackout in Fallon


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