Yesterday, an active region on the sun – basically, a collection of magnetically active sunspots – popped off a series of flares that were actually fairly energetic. NASA’s Solar Dynamics Observatory caught the action in this video:
Neat! These shots were in the ultraviolet, where flares are easier to spot.
Sunspots are where the Sun’s complex magnetic field pokes through the surface. The field lines store ridiculous amounts of energy (did you see my BAFact for today?), and allow plasma – superheated, ionized gas – to flow along them. Think of these field lines like a pillowcase full of tightly wound springs. If one of them snaps – which can happen if they get too close to each other, for example, or when the churning surface of the Sun ratchets up the tension in the field lines beyond their capacity to restrain themselves – it blasts out its energy, which then snaps other lines, which release their energy, and so on. You get a cascade of explosions, resulting in a solar flare.
Flares can be pretty small, or hugely huge. Scientists categorize them by the amount of X-ray energy released, so we have low-energy C class, medium M class, and yikesingly X class. This flare from yesterday just edged into X class territory, so it was decent, but not too bad. Happily it was on the edge of the Sun, and the blast was directed away from Earth, so it’s not expected to affect us. For further reassurance, there have been 14 previous flares since this new sunspot cycle began a couple of years ago, and we’re still here.
However, as the Sun spins, this active region is rotating toward us. If it stays active, we could see some interesting events from it that can cause aurorae on Earth. The odds of anything bad happening – power outages, or loss of satellites, for example – are low, but not entirely zero. I personally am not too worried about it, but it’s always good to keep our eyes on our nearest star. It can pack quite a punch, and we’re still a year or so away from the peak of the current sunspot cycle.
Image credit: NASA/SDO
Early this morning, while you were sleeping, or working, or reading Twitter, the Sun had different plans: it erupted, blasting an immense tower of plasma upward off its surface:
[Click to enheliosenate.]
This image was taken by NASA’s Solar Dynamic Observatory at 08:15 UTC this morning. The scale of it is staggering. The Sun is 1.4 million kilometers across – 860,000 miles – so this plume was at least 400,000 km long. Going back through the images, it had been brewing for hours, but really got its start around 05:00, meaning it erupted upwards at well over 100,000 km per hour. That’s fast enough to cross the face of our planet in less than 8 minutes.
By the way, did I mention the total mass of such a prominence is billions of tons? And the Sun does this kind of thing all the time.
We’re in no real danger from an eruption like this, especially this one: it’s on the Sun’s limb, so it was heading away from us. But these events can trigger storms like coronal mass ejections, where billions of tons of material is sent hurtling across the solar system at mind-crushing speeds. Those can interact with our magnetic field, creating havoc with our satellites and causing power outages.
But that’s why we keep an eye – many eyes, in fact – on our Sun. Never forget: our Sun is a star, with all the power and fury that implies. The better we understand it, the better we can protect ourselves from it when it gets angry.
Image credit: NASA/SDO. Tip o’ the welder’s glasses to Camilla SDO.
On August 31, the Sun threw a major tantrum. It started with a vast arc of material towering over its surface, a stream of plasma flowing between two sunspots. Sometimes these collapse back down to the Sun’s surface, but this one exploded, blasting hundreds of millions of tons of material out into space.
SDO captured this ridiculously awesome picture of the arc just before it erupted:
Holy solar hissy fit! [Click to enfilamentenate.]
This picture is a combination of two images, both in the extreme ultraviolet part of the spectrum (30.4 and 17.1 nanometers, to be specific), where magnetic activity is easy to spot. The bright spot to the upper left is a sunspot, which are normally dark in optical light, but shine brightly in the UV. The filament, as the arch is called, is so big it’s hard to comprehend: it was something like 300,000 kilometers (nearly 200,000 miles) across! That’s nearly enough to extend from the Earth to the Moon.
Having a hard time picturing that? Yeah, me too. Happily, NASA provided an image with the Earth for comparison. Yegads. And there are more images of the event on the NASA/Goddard Flickr page.
Stephen Ramsden is an astronomer who runs the Charlie Bates Solar Astronomy Project, and he saw it while at Dragon*Con! I was at D*C but totally missed this, but he got a very cool picture too. As you can see in this picture, it was erupting when he caught it. I’m kicking myself to have missed the solar observing at the con, and next year I’ll be sure to take a look. I’d hate to miss something like this again!
For his non-profit Charlie Bates Solar Astronomy Project, Stephen takes solar telescopes across his region and uses them to teach people (including kids!) about the Sun and its effect on us. I’ll note he accepts donations to help him do this. Hint hint.
Finally, I’ll add that this amazing solar eruption traveled outward at about 1500 kilometers per second (900 miles/second) and nicked the Earth’s magnetic field on September 3, sparking aurorae in extreme latitudes. This had little real impact on us, but I gently remind you the Sun is still not at its peak. It’ll reach the max of its cycle next year sometime, and the biggest flares and other storms tend to happen a few months after the peak. It’s hard to say if this will do any damage – loss of satellites and power blackouts are possible, though no direct harm to humans on Earth can happen – but we’ll see. The most likely outcome is aurorae, so keep your browser tuned to the NOAA Space Weather Prediction Center and SpaceWeather. If we do get aurorae, those are great places to let you know.
Images credit: NASA/GSFC/SDO; Stephen Ramsden
It’s been a while since we’ve had a big flare from the Sun. Active region 1515 was looking like it might do the trick — over the past week this group of sunspots has been hissing and spitting, but the flares have been relative small. Astronomers rate flares by their X-ray energy: A, B, C, M, and X, where X is the highest. Some of the flares from AR1515 were C class and some M class – moderately strong.
Between July 5 and 6 it put out about a dozen of those smaller flares:
Then, late on July 6, it blew out the first X-class flare of the summer:
This sequence of images from the Solar Dynamics Observatory shows the flare over a bunch of different ultraviolet wavelengths, where flares are most obvious. You can see that it was pretty bright! Here’s a video showing it erupting:
The video again shows the Sun at different wavelengths of UV light. The flickering is due to the software automatically setting the brightness level; when the flare gets bright it sets the image to be dimmer, so the Sun appears to flicker. The long dashed-line spikes are not real; those are due to the way the detector in SDO sees X-ray light, like the spikes you see in bright stars in some telescopic images.
Flares occur when the Sun’s magnetic field gets tangled up. In a sense, the field short-circuits, releasing vasts of built-up energy, and we call that a flare. A big one can release 10% of the entire energy of the Sun! This can emit high-energy light and a huge blast of subatomic particles which cross the inner solar system and slam into us. While we’re safe on the ground, this can damage satellites, cause blackouts, and of course trigger gorgeous aurorae — the northern and southern lights.
This flare was still pretty small even for an X class; we had bigger ones over the past year (see the Related Posts for links to some of those). This particular group of sunspots is heading over the edge of the Sun now as our star rotates, so we probably won’t be seeing it again; sunspots tend not to last that long. But there will be more. We’re still approaching the peak of the sunspot cycle, probably late next year, so expect plenty more — and more powerful — flares to come.
Tip o’ the welder’s goggles to Camilla Corona SDO on Google+. Image credit: NASA/SDO
- HD Footage of last night’s flare
- The Sun lets out a brief flare
- The Sun aims a storm right at Earth: expect aurorae tonight!
- GORGEOUS solar eruption!
- The birth of a sunspot cluster
Active sunspots are pretty dramatic all by themselves, but a little over-the-top music can’t hurt.
This spot has been spitting out some low-level activity, but the Sun is tricksy. We’ll see if we get some bigger ones as this thing rotates in our direction over the next few days. Be on alert for aurorae!
This is what I’ve been waiting for: the stunning video views of NASA’s Solar Dynamics Observatory of the Venus transit. Sit down, set this video to high-def, tune out everything else for 3 minutes 7 seconds, and soak in the clockwork glory of our solar system.
OK, you can breathe now. NASA has provided high-resolution versions for download, too.
SDO orbits the Earth about 40,000 kilometers (24,000 miles) above the surface of the Earth, with a nearly-continuous view of the Sun — so it had the best seat in the Universe for the transit. One of its most important tasks is to observe the Sun in ultraviolet, where our star’s magnetic activity is most obvious. The views in the video show the Sun different parts of the ultraviolet spectrum, colored to make them easier to see: magenta is at 1700 Angstroms (a unit of length astronomers like; 100 million Angstroms would comfortably fit across your fingernail), red is 304 Angstroms, and gold is 171 Angstroms. The orange segment is from the light we can see, about 3000 – 7000 Angstroms.
The Sun’s ethereal outer atmosphere, its corona, glows at at 171 and 304 Angstroms. In visible light the transit lasted about 7 hours, but in the UV it took longer since the silhouette of Venus can be seen against the softly luminous corona.
SDO was commanded to take images faster than usual, to provide as much coverage of the transit as possible, so the passage of the planet across the Sun is smooth and — I know, but it fits — other-worldly.
And I can’t help but think about a sad milestone today: one of America’s — one of the world’s — greatest writers, Ray Bradbury, has died. Among his many works was "The Long Rain", a short story which took place on Venus. It had a huge impact on me when I first read it as a kid, and it still makes me think about human nature, space exploration, and what happens when we mix the two.
Bradbury was more than a writer, he was a poet, and his works inspired generations of people to look beyond the borders of our world while still considering our humanity. We all must go someday, and for him to do so on the eve of the last transit of Venus to be seen for over a century is, somehow, fitting.
Ray Bradbury knew that no matter where we are, whether we are looking down into the water of another world, or looking up into the skies, what we are always seeing is a reflection of ourselves.
Sic transit gloria mundi.
Right now as I write this, the Sun is settling down after a minor flare tripped a flippin’ huge and spectacular prominence: a looping tower of plasma hundreds of thousands of kilometers high! Using Helioviewer.org, I created a short movie of the eruption, and you just have to see it. Make sure you have the resolution set to hi-def!
Isn’t that amazing? The flare that triggered this event was no big deal, about an M1.7, which is nothing to worry about at all. We had far bigger ones in March! But that arc of plasma — ionized gas — is astonishing. Flares happen when the magnetic field lines of the Sun get tangled, and suddenly release their vast, vast stored energy. The erupting plasma follows those field lines up and away from the Sun. Some escapes forever, and some falls back to the surface. You can easily see it flowing in these videos.
These views show the eruption in two different wavelengths, though both are in the ultraviolet, where the magnetic activity is easiest to see. My friends at NASA Goddard put up some fantastic pictures of it, like the one above [click to embiggen]. They have some video there, too.
I’ll note that the active region shown here is on the side of the Sun rotating toward the Earth right now, so if there are more eruptions in the next few days we may see some affect on Earth, like aurorae at northern latitudes. As usual, you don’t need to panic about this stuff. The worst it can realistically do here on Earth is cause blackouts if a particularly big storm overloads our power grid. And while that would be irritating, it’s unlikely. So sit back and enjoy the show!
[Edited to add: Some folks are asking how long this event took; it went from start to finish in just a few hours. Another common question is how big the Earth would be compared to this, and the answer is: really really teeny. Check out the curve of the Sun's edge, and remember that the Sun is over 100 times the diameter of the Earth!]
Credits: NASA/SDO/helioviewer.org. Music: “Feral Chase” by Kevin MacLeod.
- Desktop Project Part 8: From filament to prominence
- The Sun decided to blow off a little steam today. Twice.
- Gorgeous flowing plasma fountain erupts from the Sun
- A fiery angel erupts from the Sun
[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
The Solar Dynamics Observatory is a NASA satellite that observes the Sun 24 hours a day. It orbits the Earth, placed carefully so that it takes 24 hours to circle the Earth once — what we call a geosynchronous orbit. This maximizes its output, and allows scientists to squeeze as much data from it as possible.
But, twice a year, the geometry of SDO’s orbit aligns in such a way that the Earth itself gets between the observatory and the Sun. When that happens, you get an eclipse! We’re in one of those "eclipse seasons" now, and around midnight last night UTC one such eclipse occurred. The folks at SDO created a nifty video from the images collected during that time:
That’s cool. You can see the Earth barreling through the image, blocking SDO’s view. SDO has several different cameras which look at the Sun at different wavelengths of ultraviolet and optical light. The first view, colored red, is actually in ultraviolet (at 304 Angstroms, if you’re keeping track). The next view, colored gold, is even further in the UV (193 Angstroms). Then they cycle through a bunch of different wavelengths, giving a psychedelic journey through an eclipse that reminds me of the ferry ride from "Willy Wonka".
"There’s no earthly way of knowing, which direction we are going…"
I’ve written about all this before; see Related Posts below for more.
And I’ll leave you with this question: when the Moon passes between the Earth and the Sun, it’s a solar eclipse, and when the Earth passes between the Sun and the Moon, it’s a lunar eclipse. So what do we call it when, for us on the surface, the Earth gets in between us and the Sun?
Tip o’ the dew shield to Camilla Corona SDO on Google+.
Around midnight UTC last night, Active Region 1429 on the Sun exploded with a fairly large flare: rated at class X5.4, it was among the largest seen in the current cycle.
Video of the flare has been created using images from the Solar Dynamics Observatory:
Yowza. This flare was big enough that it may cause some communication issues and will probably lead to some nice aurorae, but otherwise is no danger to us here on Earth. I haven’t heard much else, but I’ll update this as I do.
Tip o’ the SPF 5000 to Camilla Corona SDO.