The Sun aims a storm right at Earth: expect aurorae tonight!

By Phil Plait | January 24, 2012 6:00 am

Around 04:00 UTC on Monday morning, January 23, 2012, the Sun let loose a pretty big flare and coronal mass ejection. Although there have been bigger events in recent months, this one happened to line up in such a way that the blast of subatomic particles unleashed headed straight for Earth. It’s causing what may be the biggest space weather event in the past several years for Earth: people at high latitudes can expect lots of bright and beautiful aurorae.

I’ll explain what all that is in a second, but first here’s a video of what this looked like from NASA’s SOHO satellite.

Wow! Make sure you set it to high def.

So what happened here? The sunspot cluster called Active Region 11402 happened.

Sunspots are regions where the magnetic field lines of the Sun get tangled up. A vast amount of energy is stored in these lines, and if they get squeezed too much, they can release that energy all at once. When this happens, we call it a solar flare, and it can be mind-numbing: yesterday’s flare exploded with the energy of hundreds of millions of nuclear bombs!

In the image above, the sunspots are caught in mid-flare, seen in the far ultraviolet by NASA’s Solar Dynamics Observatory (it’s colored green to make it easier to see what’s what). We think of sunspots as being dark (see the image of AR 11402 below), but that’s only in visible light, the kind we see. In more energetic ultraviolet light, they are brilliant bright due to their magnetic activity.

A huge blast of subatomic particles was accelerated by the explosion. The first wave arrived within a few of hours of the light itself… meaning they were traveling at a significant fraction of the speed of light!

But shortly after the flare there was a coronal mass ejection: a larger scale but somewhat less intense event. This also launches particles into space, and these are aimed right at us. The bulk of the particles are traveling at slower speeds — a mere 2200 km/sec, or 5 million miles per hour — and is expected to hit us at 14:00 UTC Tuesday morning or so. That’s basically now as I write this! Those particles interact with Earth’s magnetic field in a complicated process that sends them sleeting down into our atmosphere. We’re in no real danger from this, but the particles can strip the electrons off of atoms high in the air, and when the electrons recombine the atoms glow excite the electrons in atoms high in the air, and when the electrons give up that energy the atoms glow. That’s what causes the aurorae — the northern and southern lights.

If you live in high latitudes you might be able to see quite the display when it’s dark — people in eastern Europe and Asia are favored for this, since this happens after sunset there. But the storm is big enough and will probably last long enough that everyone should check after dark: look north if you live in the northern hemisphere and south if you’re south of the Equator. There’s no way in advance to know just how big this will be; it might fizzle, or it might be possible to see it farther away from the poles than usual. Can’t hurt to look! Also, Universe Today has been collecting pictures of aurorae from the solar blast earlier this week. No doubt they’ll have more from this one as well.

Although big, this flare was classified by NASA as being about M9 class — powerful, but not as energetic as an X class flare. One of those popped off last September, and shortly after that a smaller M flare erupted, which also triggered a gorgeous plasma fountain called a filament on the Sun’s surface.

As I said, we’re in no real danger here on Earth, and Universe Today has a good article describing why the astronauts are probably not in danger on the space station, either. Even if this were larger storm, the astronauts can take shelter in more well-protected parts of the station, too. Bigger storms can hurt us even on Earth by inducing huge currents in power lines which can overload the grid. That does happen — it happened in Quebec in March of 1989 — and it may very well happen again as the Sun gets more active over the next few years. [UPDATE: a ground current surge from today’s event was reported in Norway.]

But we should be OK from this one. If you can, get outside and look for the aurorae! I’ve never seen a good one, and I’m still hoping this solar cycle will let me see my first.

Image credit: NASA/SOHO; NASA/SDO

Related posts:

Awesome X2-class solar flare caught by SDO
Gorgeous flowing plasma fountain erupts from the Sun
NASA’s guide to solar flares
The comet and the Coronal Mass Ejection


Comments (30)

  1. And it just has to be cloudy tonight. I think I’m going to scream.

  2. Chris

    Argh, it’s cloudy here every time there are auroras!

  3. For folks who are interested in tracking the possibility of seeing anything (assuming favourable skies), you may be interested in this link:

  4. renke

    completely off-topic, I’m just curious…

    Is there a rule of thumb how to name multi-stakeholder space missions? I often read “NASA/ESA HST” (both and don’t even mention ESA on the start page :)), but here you call it NASA’s SOHO ( shows both agencies’ logos, although the site is hosted by NASA).

  5. Jeff

    I actually did observe a powerful all-night aurora in Orlando, of all places, back in 1989. I was looking at sunspots that day and there were a ton then. I really hope the next cycle if I’m still here, I hope it isn’t a maunder minimum-type thing for the mid 2000s,

    I don’t know about you, but I really hate sunspot minimum, I can’t show anything I do on sun then.

  6. SkyGazer

    Can´t wait to see how the climaet change deniers are going to twist this into their denial blablabla.

  7. Wzrd1

    Wow! I called Ripley to tell them that for once, it won’t be cloudy here when a celestial event is going on.
    They didn’t believe it.
    That can mean only one of two things. Either I’ll actually get to see it OR, far more likely, every neighbor for miles around will turn on their outside lights.

  8. Peptron

    “… they were traveling at a significant fraction of the speed of flight!”.

    Has mental image of a sparrow flying with all its birdly might, overtaking a solar blast.

  9. dw

    Maybe I’ve read too much science fiction as a kid, but every time someone says to go out and watch the light show in the sky, I expect triffids to show up the next day.

  10. kevbo

    @8 Peptron:

    What do you mean? An African or European swallow?

  11. dana

    Will this possibly effect cell phone service in any way? Like, say, randomizing the texts sent to different recipients?

  12. Chris

    Looking at the solar wind data from spaceweather. Noticed the wind speed has been stuck around 300 km/s and temp stuck around 10^5 K for the past day and a half. Are the instruments OK?

  13. Peptron

    @ kevbo:
    I don’t know that!

  14. mike burkhart

    I just heard aout this, some were saying that the internet would crash but since I posted this clearly that has not happened.To DW#9 I’ve seen that movie to, and after I watched many meteor showers I still have my eyesight . Meteor showers are not bright enofe to cause blindness. Also most burn up so if there Trifid seeds on them they would burn up to. One more thing Don’t knock beeing a sci- fi fan be proud of it. Off topic: You will love this Phil I downloaded google Earth ,it comes with google Moon,Mars ,Night sky . they have added a flight simulator game to it In witch you are flying a plane (propler or jet) over the Earth.Now the funny part, it also works on google moon and mars!Thats right you can fly your plane over the surface of the moon or mars ! its fun but a plane engine Propler or jet won’t work on the moon or mars due to lack of oxygen.

  15. alfaniner

    I guess I tend to confuse Coronal Mass Ejections with Gamma Ray Bursts. For one, everybody sighs — for the other, everybody dies.

  16. DrFlimmer

    @ renke (and BA)

    I was about to complain about the same thing. According to the information on their webpage SOHO was mainly built in Europe and is now operated by NASA at the Goddard Space Flight Centre. That means ESA has done very important stuff for this mission, and should be mentioned here.
    As a matter of fact (if I remember this fact correctly 😉 ), I think in previous times SOHO was mostly referred to as “ESA’s SOHO”. Somehow I have the impression that I read “NASA’S SOHO” for the first time.

    Anyway, it’s cloudy here, too. And waaaay to bright due to lightpollution.

  17. I was fascinated by CNN’s heavy-handed “oh noes, radioactive particles stream towards Earth!” article.

    That’s the sort of reporting you get after a major news network fires their entire science staff.

  18. Daniel J. Andrews

    Sweden web cam shows the aurora in display right now 1 p.m. EST.

    edit: it is quite a spectacular one too. wow.

  19. tim Rowledge

    a plane engine Propler or jet won’t work on the moon or mars due to lack of oxygen.

    True for the Moon but not for Mars. Mars is a bit short on atmosphere (lousy discos there) but has enough for a Mars plane to be seriously considered.
    Models have been built and tested by dropping from a high-altitude balloon.

  20. Anchor

    Phil, here’s hoping you will at long last witness a good display…during this solar max. (Alas, the activity might diminish substantially for the rest of our lives…agh!!!)

    They really are one of those rare phenomena in the sky that is best appreciated by the unaided eye, and when it’s strong and really popping the spectacle far exceeds any photographic or video record. Ask anybody who knows.

    I still strongly recommend and urge you to take measures to get north to a suitable high-probability latitude to get a decent view. Find a way to spend a couple of weeks at the latitude of Hudsons Bay sometime this year. If you get under the auroral ring and time it with the weather pattern, you’ll very likely catch one. Make it a fishing trip, or whatever. You’ll have a decent chance of catching a decent display. It is absolutely worth it if you get so much as a half an hour of activity.

    I’ve seen lots of things in the sky that have taken my breath away, but the three most awesome sights I’ve experienced, in order of increasing anoxia, were: 3. Comet Hyakutake, with a tail that stretched over 60 degrees across the sky, 2. The Total Solar Eclipse of July 11, 1991 seen from near the centerline north of Puerto Vallarta, Mexico, and 1. ANY OF A FULL DOZEN of truly spectacular aurora displays I’ve been fortunate to have witnessed by shear chance…from WISCONSIN. Those displays came to me, but during that same 2o+year interval I have missed fully three times that many exceptional displays, I am informed by friends in a more favorable northern position, because of weather or just because I was located a mere couple of hundred miles south of where the main action was happening.

    Do yourself a favor, especially in case the Sun does another Maunder Minimum gig that would foreclose any chance for getting a display at your latitude: GO NORTH, ASTRONOMER MAN!

    BTW: no joy here from this particular CME tonight. Had hopes, but the arrival timing for North America was rotten – the impact happened too early during the day, and by nightfall there was only a diffuse glow on the northern horizon to be discerned.

  21. The ground current surge was not in Sweden, but Norway.. In Lofoten.

  22. osaze

    I just got an sms and I live in a timezone of GMT+1 just got news from NASA about some cosmic rays hitting earth. also u r to switch off ur phones on April 5th, 2012 btw 12:30am and 3:00am tomorrow. do well to save some lives.

    Could this be some false alarm???!?!?!

  23. Ricardo

    What happened with SOHO? I’ve tried to access SOHO but I can’t…thank you…

  24. Ricardo

    I have some photos of our sun very strange. I think were some of the latest of SOHO images. I know that magnetic fields may have influenced in what I saw in the sun … but what happened to SOHO?


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!


See More

Collapse bottom bar