In this video, we're going to explore a little bit of what helioveure.org is able to provide for us so that we can actually see what we're going to be learning about in the chapters on the Sun. So when you first get to helioveure, it may not show you this particular imagery, but it should provide you with an option to go through a tutorial. I highly recommend trying that on your own. But what I'm going to show you is just a couple of useful comparisons so that we can actually see the structures that we're learning about in our textbook. So I went to a day back when the Sun was very active. So in the year 2013, the Sun was active and we had available to us the Solar Dynamics Observatory. Now helioveure can provide imagery and data from a lot of different spacecraft. We're going to just look at a couple of wavelengths from Solar Dynamics Observatory, SDO. And SDO has several different instruments that we can investigate. AIA, the atmospheric imaging assembly, is the one that actually takes pictures of the Sun. HMI takes magnetic data and so we're not going to focus on that one. The measurement here is in angstroms. So all of these are numbers for wavelengths. We talked about wavelengths when we thought about the nature of light. 4,500 angstroms or 450 nanometers is within the visible light range. And so we're going to use that as our stand-in for a visible picture of the Sun. Now a much smaller number wavelength means a shorter wavelength, higher energy form of light, that is going to be extreme ultraviolet. All of these here that are three digits of angstroms would be extreme ultraviolet. And we're going to use 193 just because I think it shows the structures that we care the most about quite easily. Up in the corner there's the Earth to scale so that you have a sense of the structures that we're looking at how they compare to our own home planet. So the first thing I'm going to do is show us what it looks like if we go back and forth between the visible image and the extreme ultraviolet. Now the key thing here is that when we shift from one form of light to the other, if you look right here at the limb of the Sun, that might be the easiest way to see that this is beneath the layer that we're looking at here. When we're looking at the visible kind of yellow colored Sun for us here, we're looking at what is called the photosphere, the so-called surface of the Sun, although it is not a solid surface. And when we remove that to look at this extreme ultraviolet image, we are looking at the corona of the Sun, which is a part of the Sun's atmosphere above the so-called surface layer. So this is in the corona and down below it, we're in the photosphere. Okay, so a couple of key things that I want to point out here. In this area, we see a really good Sunspot group. If you look at data from more recently, 2018, 2019, and so on, there aren't that many Sunspots that show up. The Sun has been in a minimum for a while. But there's a couple of Sunspot groups. And what's really important to notice is that underneath those Sunspot groups, the big one on the right here and the smaller one on the left, underneath both of those Sunspot groups, we see bright loops of material, what we call active regions. And we can even convince ourselves that that's what these are by clicking the button here to tell us out of these three different catalogues, I'm just going to use the one that highlights the active regions for us that aren't too many to count. So this particular catalog is telling us that this is one big active region. It had a name. This one is two. And okay, so the active regions, if we go back to the visible light, the active regions are showing up right where Sunspots are. Those two structures are connected. Sunspots are telling us in the visible light that there is strong magnetic field in that area. And active regions in extreme ultraviolet light are showing us loops of material that are following along those strong magnetic field lines. The other thing that we can highlight are coronal holes. So now I have active regions AR and coronal holes CH shown for us. The coronal hole here, if we toggle it on and off, we can see that coronal holes are places in the corona where we're looking at the extreme ultraviolet places in the corona where it is darker. It is darker because there is less material there that is trapped low down in the corona. If we look at these same regions in the photosphere, there doesn't seem to be anything indicating to us that those are coronal holes. That's why I really want to make it clear to us that a lot of students they'll often confuse Sunspots and coronal holes simply because they are things that look dark in the imagery where we see them. But we can notice the difference in location on this image. They are not the same structure. Coronal holes are in the corona and they look dark only in extreme ultraviolet. They look dark because there is less material there. Sunspots, they only look dark in the photosphere, invisible light images and they look dark not because there's less material but because that material is colder. So they're even dark for different reasons. So it is worth making sure that we can make those connections between what things are related to each other, active regions and Sunspots and what things are not related to each other, coronal holes and Sunspots. So hopefully this was a useful overview of Healy of Youre. I highly recommend that you check it out for yourself. One nice thing you can do is you can take screenshots of what you're viewing. You can select a particular area that you want to take an image of and then you'll be able to download that information. So thanks for listening and I will see you in the next video.