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 ...
[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 ...
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 ...
I was fooling around with helioviewer.org, watching the flare in different wavelengths of light detected by NASA’s Solar Dynamics observatory, when I switched to 17.1 nanometers — in the far ultraviolet. At that wavelength, the glowing plasma that flows along the Sun’s magnetic field lines is very bright. The images were so beautiful, so incredible, I made a video animation of them, covering the time range of January 26, 2012 at midnight to January 28 at noon (UTC), which includes the huge X2 solar flare that erupted on the 27th. The video shows huge loops of magnetism on the Sun’s surface, glowing plasma flowing along them… and then 48 seconds in the flare changes everything. Watch:
Holy wow! Isn’t that awesome? Make sure you watch in in HD, and make it full screen to get the whole effect.
What you’re seeing is Active Region 1402, a sunspot cluster. This is a tangled collection of magnetic field lines piercing the surface of the Sun. Like ...
Active Region 1402, the same sunspot cluster that blew out a solar flare and caused all the ruckus last week, is still being feisty: just before rotating to the other side of the Sun, it erupted in an intense, pulsing solar flare that actually was much more powerful than the one that happened last Monday. This was an X2 class flare, making it more than twice as energetic as Monday’s.
Happily, the flares were on the edge of the Sun’s disk, so the bulk of the radiation was aimed away from the Earth, but it still makes for some pretty dramatic footage. Using helioviewer.org I created a video showing about 2.3 hours of the Sun as seen by NASA’s Solar Dynamics Observatory. It shows the Sun in the extreme ultraviolet (at a wavelength of 19.3 nanometers if you wanna get geeky), where magnetic activity is seen easily. Watch the upper right corner of our friendly star… and make sure you make it HD and full screen.
Isn’t that awesome? The flare got so bright the automatic software dimmed the rest of the Sun to compensate, giving you an idea of just how powerful ...
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.
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.
In July of last year, I wrote about a comet that passed extremely close to the Sun. Astronomers have now had a chance to pore over that data, and were able to determine some very cool stuff.
See it? It’s faint, but there. Actually, there are a lot of observations from multiple observatories and detectors, which allowed astronomers to find out quite a bit about this doomed chunk of ice and rock.
For one thing, it was screaming along at about 650 kilometers per second (400 miles/second) as it flamed out. To give you an idea of how flippin’ fast that is, it would’ve crossed the entire United States in about eight seconds.
Yeah, I know.
It also passed an incredible 100,000 km (62,000 miles) above the Sun’s surface. Have you ever stood outside on a hot day, and thought the Sun would cook you? Now imagine the Sun filling half the sky. That’s what that comet saw. No wonder it disintegrated.
As it approached the Sun, it was watched by NASA’s Solar Dynamics Observatory. In its final 20 minutes or so, the comet broke up into a dozen pieces ranging from 10 – 50 meters in size (and no doubt countless smaller ones too small to detect), with a tail of vaporized material streaming behind it that went for thousands of kilometers. For that size, it would’ve had a mass of hundreds of thousands of tons — about what a loaded oil tanker weighs on Earth!
We’ve learned a lot about how comets break up and disintegrate by observing this event, but it’s raised further questions: like, why did we see this at all? Comets are faint, and to be able to see it this way against the bright Sun is odd. It was definitely one of the brightest comets seen, but it’s interesting to me that it appears to glow in the ultraviolet, as it did in the above video. That means, at that wavelength, it was brighter than the Sun! It wasn’t like a meteor, burning up as it slammed through material, so some other process must have affected it. I suspect that the Sun’s strong magnetic field may have had something to do with it; in the far ultraviolet magnetism is a strong player. Gas under the influence of intense magnetic fields can store a lot of energy, which is why sunspots — themselves the product of magnetic squeezing — look bright in UV.
Perhaps as the comet broke up, the particles inside got excited by the magnetic fields of the Sun and glowed. I’m no expert, and I’m spitballing here. The thing is, no one is exactly sure. But that doesn’t mean we won’t find out. Nothing makes a scientist’s noggin itch as much as a mystery like this, something apparently misbehaving.
One of the single most important words in science is "yet". We don’t know yet. But we will. Someone’ll figure this out, and we’ll have one more victory in our quest to better understand the Universe.
Comet Lovejoy was only discovered in late November, but it’s had quite a ride. It was quickly determined to be a Sun-grazer, the kind of comet that plunges down very close to the Sun in its orbit. The date of this solar close encounter: yesterday!
That’s a shot of it using SOHO, a solar observatory orbiting the Sun. The Sun itself is blocked by a mask, and the white circle represents its outline. The comet is obvious enough! The line through the top of it is not real; that’s called blooming and it happens sometimes when a bright object is seen by a digital detector. The electrons in the chip overflow the pixels and leak into adjacent ones. The comet got very bright as it neared the Sun, almost as bright as Venus! This picture, taken on December 15th at 22:36 UT, was shortly before closest approach: a mere 180,000 km (110,000 miles) from the Sun’s searing surface.
Amazingly, after the comet screamed past the Sun, and to the surprise of many, it survived. A lot of comets don’t make it through such an event, but this one did. Here’s a video of the comet reappearing from behind the Sun, as seen by SDO; watch closely or you’ll miss it!
Nifty. But on the way down it had several interesting things happen to it. It had a companion (scroll down to December 14, 19:00 UT for the short video and tip on how to see the very faint second comet), for one. For another, it developed two distinct tails, which happens in comets fairly often. One is made of dust — ground up rock, essentially — and the other gas that gets ionized as it’s stripped off by the solar wind.
My favorite video shows the comet approaching the Sun as seen by STEREO; a special processing technique was used involving subtracting successive frames in the sequence, which eliminates the bright background and leaves sharper objects like stars and comets… and ripples in the solar wind. Watch as the comet moves toward the Sun, and see the tail wiggle as changes in the density of the solar wind buffet the beleaguered traveler:
Isn’t that cool? And how long do you think it’ll take some person with, um, odd sensibilities to use this video to claim the comet is alive, and some sort of cosmic spermatozoa?
But if you’d rather stick to facts — because c’mon, this is pretty amazing stuff already – then check out the fun Geeked on Goddard blog (and follow them on Twitter), as well as the Sungrazer website for more info on this scrappy little comet.
Comet Lovejoy was only discovered in late November, but it’s had quite a ride. It was quickly determined to be a Sun-grazer, the kind of comet that plunges down very close to the Sun in its orbit. The date of this solar close encounter: yesterday!
That’s a shot of it using SOHO, a solar observatory orbiting the Sun. The Sun itself is blocked by a mask, and the white circle represents its outline. The comet is obvious enough! The line through the top of it is not real; that’s called blooming and it happens sometimes when a bright object is seen by a digital detector. The electrons in the chip overflow the pixels and leak into adjacent ones. The comet got very bright as it neared the Sun, almost as bright as Venus! This picture, taken on December 15th at 22:36 UT, was shortly before closest approach: a mere 180,000 km (110,000 miles) from the Sun’s searing surface.
Amazingly, after the comet screamed past the Sun, and to the surprise of many, it survived. A lot of comets don’t make it through such an event, but this one did. Here’s a video of the comet reappearing from behind the Sun, as seen by SDO; watch closely or you’ll miss it!
Nifty. But on the way down it had several interesting things happen to it. It had a companion (scroll down to December 14, 19:00 UT for the short video and tip on how to see the very faint second comet), for one. For another, it developed two distinct tails, which happens in comets fairly often. One is made of dust — ground up rock, essentially — and the other gas that gets ionized as it’s stripped off by the solar wind.
My favorite video shows the comet approaching the Sun as seen by STEREO; a special processing technique was used involving subtracting successive frames in the sequence, which eliminates the bright background and leaves sharper objects like stars and comets… and ripples in the solar wind. Watch as the comet moves toward the Sun, and see the tail wiggle as changes in the density of the solar wind buffet the beleaguered traveler:
Isn’t that cool? And how long do you think it’ll take some person with, um, odd sensibilities to use this video to claim the comet is alive, and some sort of cosmic spermatozoa?
But if you’d rather stick to facts — because c’mon, this is pretty amazing stuff already – then check out the fun Geeked on Goddard blog (and follow them on Twitter), as well as the Sungrazer website for more info on this scrappy little comet.
On November 15, the Sun had a minor eruption on its surface that launched a prominence — a towering arc of ionized gas — into space. Sometimes these prominences collapse back down to the surface, and sometimes they wind up ejecting that material into space. This one did a little of both:
The animation was made from images taken over the course of 13 hours by the Solar Dynamics Observatory. The images are false-color; what you see as orange is really ultraviolet light, where the energized gas glows brilliantly. This particular event sent some gas more or less toward Venus, where probably not much will happen. This isn’t like a major flare or coronal mass ejection… but it’s still cool.
Prominences occur all the time (click the picture here to see a gorgeous one from last year), and generally don’t wind up affecting us here on Earth. Still, it’s fascinating to watch the gas — which is hot enough to have its electrons stripped off its atoms, so it follows the Sun’s magnetic field as strongly or even more strongly than it does the Sun’s gravitational field — writhe and seethe under these tremendous forces.
But shortly after the flare there was a 
