Ever wanted to see how sunspots form and change as they grow? The folks working with NASA’s SDO satellite just released this amazing video of the adorable younglings.
Not much happens until about 18 seconds in, and then a lot happens.
That is so freaking cool. Taken over the course of two weeks (half a rotation of the Sun), you can see them pop up, darken, and grow, and even rotate a bit as the Sun’s complex magnetic fields change… and the neatest part to me is the foreshortening they undergo as they approach the east side of the Sun’s disk. Amazing!
Sunspots are actually regions of slightly cooler material at the Sun’s surface. Hot plasma (ionized gas, stripped of one electron or more) rises from the solar interior, reaches the surface, cools off, and sinks back down. This is called convection, and is the same process you see in a pot of boiling water. But at the surface, the tortured and twisted magnetic field of the Sun can suppress convection, preventing the cooler material from sinking. Since the brightness of the plasma depends on the temperature, this cooler stuff is darker. Boom! Sunspot.
Or, in this case, sunspots. You can see five of the suckers here, changing and mutating as the plasma interacts with the magnetic field. I recognize these spots, too: they were responsible for the first X-class flare of the season on March 15th. There’s dramatic footage of that as well which I posted on my blog at the time. They’re busy spots; they blew out a lower energy flare a few days earlier, too.
And here I am calling them cute and little when they’re actually comfortably bigger than the Earth and exploded with the energy equivalent of millions — millions! — of nuclear bombs.
Good thing they’re 150 million kilometers away. That lessens the impact, but doesn’t negate it. The more we learn about the way sunspots behave, the better. SDO, STEREO, and the rest of our sunward-looking fleet are teaching us a lot about our nearest star. And we’ll need that information as we enter the beginning of yet another solar cycle.
Video credit: NASA/SDO
[Click to enfilamenate.]
That was taken by the Solar Dynamics Observatory at about 17:50 UT, or just an hour or so ago as I post this. Wow! That prominence must be nearly a million kilometers across! [Update: Geeked on Goddard estimates it at 700,000 km.] Mind you, on the scale of this image, the entire Earth would be about 5 pixels in size.
OK, a few things:
1) First, there is very little danger to Earth from this event. Prominences like this tend to be local to the Sun, and collapse after a few hours. As far as I can tell, there are no flares or coronal mass ejections associated with this, which are what can hurt satellites and power grids here at home. So rest easy, and enjoy the beauty of this thing.
[Note: At the bottom of this post is a gallery of amazing pictures of the Sun from Earth and space!]
It’s so easy to take the Sun for granted. Too bright to even look at, we tend to think of it as a featureless white (or, misleadingly, yellow) disk, bereft of detail.
But then you see something like this, and it’s like a physical blow to your brain:
[Click to get access to the massive 2400 x 2500 pixel version of this (once there, click the "download" link).]
Holy heliotropism. Seriously.
What you’re seeing here is small region on the Sun’s surface at incredible resolution. This image shows an area of about 200,000 by 200,000 km (120,000 x 120,000 miles), only about 0.5% of the Sun’s visible disk. Yet the detail is amazing! The full-res version of this image shows features as small as a couple of hundred kilometers across — bear in mind, the Sun is a whopping 1.4 million kilometers (860,000 miles) in diameter!
To give you an idea of what you’re seeing, take a look at that sunspot in the lower right corner. See the roughly disk-shaped dark inner portion of it? Yeah, that’s the same size as the whole frakking Earth!
Here’s a zoom of the sunspot, taken in a way to show more detail:
Holy wow! Sunspots are where the Sun’s magnetic field breaks through the surface. Plasma — that is, gas stripped of one or more electrons, allowing it to be affected by magnetic fields — under the influence of that magnetic field cools off, so it doesn’t emit as much light as the rest of the surface. That makes sunspots look dark in contrast, but if they were floating by themselves in space they’d actually be very bright (think of a flashlight in front of a spotlight if that helps). Look at all the tendrils and structure inside the spot; that’s all due to the way the gas is flowing under the influence of the tremendous heat of the Sun and its powerful magnetic field.
I keep thinking there’s nothing new under the Sun– or on it. With SOHO, and SDO, and a thousand other telescopes pointed at it, it would take something pretty freaking cool to surprise me.
Well then. Surprise!
Holy solar retinopathy! That’s the Sun?
Yup. But this is not a space-based image from some bazillion dollar observatory! This phenomenal picture was taken by astrophotographer Alan Friedman with this relatively small (but very, very nice) ‘scope. He shot it on October 20th, and it shows our nearest star in the light of hydrogen, specifically what astronomers call Hα (H-alpha). I’ll get to that in a sec…
In this picture you can see sunspots, giant convection cells, and the gas that follows magnetic loops piercing the Sun’s surface. When we see them against the Sun’s surface they’re called filaments, and when they arc against the background sky on the edge of the Sun’s disk they’re called prominences.
The image he took is amazingly high-resolution! He has two closeups, one of the filament and sunspot near the edge of the disk on the left, and the other of prominences leaping up off the edge and silhouetted against the sky:
I’ve been posting sporadically on how sunspots are starting to come back to the Sun, and I’m glad to see a new group sprouted up recently… and it’s a monster:
These images are from SOHO, the Solar and Heliospheric Observatory. The orange one is in visible light, and the sunspots are pretty obvious. The green one shows the Sun in the far ultraviolet, and you can see the sunspots are pretty intense, blasting out high-energy light. Sunspots are indicators of magnetic activity, and the intense magnetic field can accelerate plasma (ionized gas) to high energies.
Just so’s you know, a hundred Earths could fit across this image, so that oughta give you an idea of just how big these blemishes are.
What this means is that the Sun is becoming active again. You can see it better in this video I put together using SOHO animations. These are real SOHO observations. Note that some of the data are missing so the Sun’s rotation is a bit jerky, and that you can see that data dropouts and other problems plague these sort of observations. Oh– actually, another group popped up on the Sun earlier, too, and you can see those in the visible light data.
You can actually see the plasma flowing along the magnetic field lines in the latter part of the video.
Right now, the Sun is struggling to climb back up to the peak of its magnetic cycle, which will probably occur in 2013 or later, given how slow this has been — which you might want to keep in mind if some crackpot or scammer is trying to sell you on the idea that solar activity will destroy the Earth in 2012. When the Sun is at its peak, the magnetic field is at its strongest, and we see the most sunspots. However, the strongest solar flares and other explosive events tend not to happen until well after the cycle peaks, so it’ll be late 2013 or 2014 before we see the most vigorous activity, if the Sun holds to its previous behavior.
Again, people selling you on 2012 disasters generally have a very tenuous grasp on science. The less you know the better for them.
I expect we’ll be seeing more and more sunspots now as time goes by. It’s nice to see this happening, as it adds to the activity seen in December, and ends a long period of minimal sunspots — heck, for a long time, there were none at all. Boring. Now we can look forward to some exciting action again… just in time for SDO to launch, too!
[P.S. If anyone can tell me why the first few frames of my uploaded videos turn gray sometimes, that would be nice. I don't know whether to curse iMovie, Flash, YouTube, or all three.]
Image credit: SOHO (ESA and NASA)